https://javadevcentral.com/ Recent content on Java Developer Central Hugo -- 0.134.2 en-us Mon, 27 May 2024 12:38:00 +0530 https://javadevcentral.com/google-guava-maps/ Mon, 27 May 2024 12:38:00 +0530 https://javadevcentral.com/google-guava-maps/ Google Guava Maps has many static utility methods operating on Map instances (Map, SortedMap, NavigableMap, BiMap etc.,). https://javadevcentral.com/google-guava-collections2/ Mon, 29 Apr 2024 12:33:00 +0530 https://javadevcentral.com/google-guava-collections2/ The Collections2 utility class in the Google Guava library has four methods, viz., filter, transform, permutations and orderedPermutations. https://javadevcentral.com/google-guava-sets-utility-class/ Mon, 25 Mar 2024 12:25:00 +0530 https://javadevcentral.com/google-guava-sets-utility-class/ The Google Guava Sets utility class has static utility methods pertaining to Set instances. This post covers the methods from the Sets class. https://javadevcentral.com/apache-commons-lang-objectutils/ Mon, 26 Feb 2024 12:16:00 +0530 https://javadevcentral.com/apache-commons-lang-objectutils/ The Apache Commons Lang ObjectUtils class from the Apache Commons Lang3 library has many static utility methods operating on Object instances. https://javadevcentral.com/apache-commons-comparatorutils/ Mon, 29 Jan 2024 12:05:00 +0530 https://javadevcentral.com/apache-commons-comparatorutils/ The Apache Commons ComparatorUtils provides utils for creating and using comparators from org.apache.commons.collections4.comparators package. https://javadevcentral.com/apache-commons-collections-setutils/ Mon, 25 Dec 2023 11:56:00 +0530 https://javadevcentral.com/apache-commons-collections-setutils/ The Apache Commons Collections SetUtils class has utility methods and decorators for Set and SortedSet instances. https://javadevcentral.com/apache-commons-collections-listutils/ Mon, 27 Nov 2023 11:47:00 +0530 https://javadevcentral.com/apache-commons-collections-listutils/ In this post, we will explore all the utility methods and decorators for List instances in the Apache Commons Collections ListUtils class. https://javadevcentral.com/java-stream-map-operation/ Mon, 30 Oct 2023 11:38:00 +0530 https://javadevcentral.com/java-stream-map-operation/ We use the Java Stream map (an intermediate operation) to map an element in a stream to a different value (of the same or different type). https://javadevcentral.com/java-stream-min-and-max/ Mon, 25 Sep 2023 11:33:00 +0530 https://javadevcentral.com/java-stream-min-and-max/ In this post, we will learn about using Java Stream min and max methods to find the minimum and the maximum element in a Java Stream. https://javadevcentral.com/java-stream-sorted-operation/ Mon, 28 Aug 2023 11:23:00 +0530 https://javadevcentral.com/java-stream-sorted-operation/ Using Java Stream sorted operation on a stream will return a stream with the elements of the stream sorted according to their natural order. https://javadevcentral.com/google-guava-converter/ Mon, 24 Jul 2023 18:57:00 +0530 https://javadevcentral.com/google-guava-converter/ The Google Guava Converter class represents a function to convert a value of type A to a value of type B and in the reverse direction as well. https://javadevcentral.com/google-guava-moreobjects/ Mon, 26 Jun 2023 18:51:00 +0530 https://javadevcentral.com/google-guava-moreobjects/ The Google Guava MoreObjects has helper functions to operate on any Object. It has two static methods viz., firstNonNull and toStringHelper. https://javadevcentral.com/apache-commons-lang-diffable/ Mon, 22 May 2023 18:35:00 +0530 https://javadevcentral.com/apache-commons-lang-diffable/ We can use the Apache Commons Lang Diffable to compare two objects of the same class and find the differences among the values of all fields. https://javadevcentral.com/google-guava-maps-difference/ Mon, 17 Apr 2023 18:22:30 +0530 https://javadevcentral.com/google-guava-maps-difference/ In this post, we will explore finding difference between two maps and how we can use the Google Guava’s Maps#difference method to do it. https://javadevcentral.com/apache-commons-bidimap/ Mon, 13 Mar 2023 18:06:00 +0530 https://javadevcentral.com/apache-commons-bidimap/ The Apache Commons BidiMap (a bidirectional map) is an interface using which we can perform a lookup on a map in either direction. https://javadevcentral.com/google-guava-fluentiterable/ Mon, 13 Feb 2023 15:38:00 +0530 https://javadevcentral.com/google-guava-fluentiterable/ In this post, we will learn about the Google Guava FluentIterable class which is a discouraged (but not deprecated) precursor to Java’s Stream library. https://javadevcentral.com/sealed-classes-and-sealed-interfaces/ Mon, 30 Jan 2023 15:26:00 +0530 https://javadevcentral.com/sealed-classes-and-sealed-interfaces/ Sealed classes and sealed interfaces in Java restrict which other classes or interfaces may extend or implement them. https://javadevcentral.com/java-stream-reduce/ Mon, 02 Jan 2023 15:11:00 +0530 https://javadevcentral.com/java-stream-reduce/ We use the Java Stream’s reduce method to reduce a stream of values to a single result. There are three overloaded Stream#reduce operation. https://javadevcentral.com/a-complete-guide-to-java-stream-mapmulti/ Thu, 22 Dec 2022 14:51:00 +0530 https://javadevcentral.com/a-complete-guide-to-java-stream-mapmulti/ The Java Stream mapMulti method was added in Java 16. It allows us to replace each element in a Java Stream with one or more elements. https://javadevcentral.com/google-guava-table/ Mon, 14 Nov 2022 12:51:00 +0530 https://javadevcentral.com/google-guava-table/ The Google Guava Table, part of Google Guava Collections, allows us to map a value to two ordered keys, called the row key and the column key. https://javadevcentral.com/apache-commons-lang-mutable/ Mon, 24 Oct 2022 12:36:00 +0530 https://javadevcentral.com/apache-commons-lang-mutable/ Apache Commons Lang Mutable provides mutable access to a value. In this post, we will learn about the Apache Commons Lang Mutable Class. https://javadevcentral.com/threadutils-from-apache-commons-lang/ Mon, 12 Sep 2022 12:21:00 +0530 https://javadevcentral.com/threadutils-from-apache-commons-lang/ The ThreadUtils class from the Apache Commons Lang library has helper methods for working with Java threads and ThreadGroups. https://javadevcentral.com/record-class-in-java/ Mon, 29 Aug 2022 12:05:10 +0530 https://javadevcentral.com/record-class-in-java/ Record class in Java is a new kind of class introduced in Java to help us model simple data aggregates with less ceremony than a normal class. https://javadevcentral.com/enumutils-from-apache-commons-lang/ Mon, 01 Aug 2022 11:57:00 +0530 https://javadevcentral.com/enumutils-from-apache-commons-lang/ The EnumUtils class from Apache Commons Lang provides several static methods (helper methods) for working with Java enums. https://javadevcentral.com/command-design-pattern/ Mon, 04 Jul 2022 11:48:00 +0530 https://javadevcentral.com/command-design-pattern/ The Command Design Pattern encapsulates a request as an object, thereby letting you parameterize other objects with different requests. https://javadevcentral.com/cyclicbarrier-in-java/ Mon, 20 Jun 2022 11:01:00 +0530 https://javadevcentral.com/cyclicbarrier-in-java/ A CyclicBarrier in Java is a synchronization aid which allows a set of threads to wait for each other until all threads reach a common point. https://javadevcentral.com/countdownlatch-in-java/ Mon, 30 May 2022 10:52:00 +0530 https://javadevcentral.com/countdownlatch-in-java/ A CountDownLatch in Java is a synchronization aid which allows one or more threads to wait until something else happens (or gets completed). https://javadevcentral.com/arrays-utility-class-in-java/ Mon, 16 May 2022 10:34:00 +0530 https://javadevcentral.com/arrays-utility-class-in-java/ The Arrays Utility class in Java has various methods for working with arrays. In this post, we will learn about the Arrays class in Java. https://javadevcentral.com/google-guava-lists-utility-class/ Mon, 18 Apr 2022 10:27:00 +0530 https://javadevcentral.com/google-guava-lists-utility-class/ The Google Guava Lists Utility class has static utility methods for working with a Java List. Let us learn about some useful methods from it. https://javadevcentral.com/java-18-simple-web-server/ Mon, 28 Mar 2022 19:16:00 +0530 https://javadevcentral.com/java-18-simple-web-server/ In this post, we will learn about the Java 18 simple web server (command-line tool) released as part of JDK 18. https://javadevcentral.com/java-stream-toarray/ Tue, 15 Mar 2022 19:08:00 +0530 https://javadevcentral.com/java-stream-toarray/ The Java stream toArray methods, which we learn in this post, allow us to collect/convert a stream into an array. https://javadevcentral.com/google-guava-functions/ Mon, 21 Feb 2022 18:55:00 +0530 https://javadevcentral.com/google-guava-functions/ In this post, we will learn about the Google Guava Functions utility class which has static utility methods to work on Function instances. https://javadevcentral.com/google-guava-predicates/ Tue, 15 Feb 2022 18:43:00 +0530 https://javadevcentral.com/google-guava-predicates/ In this post, we will learn about the useful static utility methods from the Google Guava Predicates class. https://javadevcentral.com/apache-commons-io-filealterationmonitor/ Mon, 24 Jan 2022 18:35:00 +0530 https://javadevcentral.com/apache-commons-io-filealterationmonitor/ Apache Commons IO FileAlterationMonitor is a runnable to notify the registered observers at specified time interval with file system changes https://javadevcentral.com/apache-commons-io-filealterationobserver/ Wed, 12 Jan 2022 18:22:00 +0530 https://javadevcentral.com/apache-commons-io-filealterationobserver/ In this post, we learn about the Apache Commons IO FileAlterationObserver - using which we can observe the state of files and directories. https://javadevcentral.com/peekingiterator-and-abstractiterator-from-google-guava/ Mon, 03 Jan 2022 18:15:00 +0530 https://javadevcentral.com/peekingiterator-and-abstractiterator-from-google-guava/ In this post, we will learn about the PeekingIterator and AbstractIterator classes from Google Guava library. https://javadevcentral.com/suppliers-utility-class-in-google-guava/ Tue, 28 Dec 2021 18:08:00 +0530 https://javadevcentral.com/suppliers-utility-class-in-google-guava/ The Suppliers class provides useful methods for working with a Supplier. In this post, we see the Suppliers utility class in Google Guava. https://javadevcentral.com/primitiveiterator-in-java/ Wed, 22 Dec 2021 17:04:00 +0530 https://javadevcentral.com/primitiveiterator-in-java/ A PrimitiveIterator in Java is an interface for the primitive specializations of an Iterator. In this post, we will learn about the PrimitiveIterator, its subclasses and its uses. https://javadevcentral.com/google-guava-charmatcher/ Mon, 06 Dec 2021 16:24:00 +0530 https://javadevcentral.com/google-guava-charmatcher/ Google Guava CharMatcher class is a Predicate for a character value. It also has basic text processing methods. https://javadevcentral.com/apache-commons-lang-charset-and-charsetutils/ Mon, 22 Nov 2021 16:17:00 +0530 https://javadevcentral.com/apache-commons-lang-charset-and-charsetutils/ The Apache Commons Lang CharSet represents a set of characters. This post covers the Apache Commons Lang CharSet and CharSetUtils class. https://javadevcentral.com/apache-commons-lang-randomstringutils/ Mon, 08 Nov 2021 16:09:00 +0530 https://javadevcentral.com/apache-commons-lang-randomstringutils/ We will learn about the Apache Commons Lang RandomStringUtils class for generating random strings for simple use cases in this post. https://javadevcentral.com/new-methods-in-the-string-class-java-11-12/ Mon, 11 Oct 2021 15:12:00 +0530 https://javadevcentral.com/new-methods-in-the-string-class-java-11-12/ A few useful methods have been added to the String class in Java 11 and 12. Let us learn about the new methods in the String class in Java. https://javadevcentral.com/google-guava-streams/ Mon, 27 Sep 2021 15:04:00 +0530 https://javadevcentral.com/google-guava-streams/ Google Guava offers many utility methods to simplify the coding. In this post, we will learn about the utilities in the Google Guava Streams. https://javadevcentral.com/google-guava-comparators/ Mon, 20 Sep 2021 14:54:00 +0530 https://javadevcentral.com/google-guava-comparators/ Google Guava library has a class called Comparators, which provides static methods for working with Java Comparator instances. https://javadevcentral.com/apache-commons-lang-pair/ Mon, 13 Sep 2021 14:45:00 +0530 https://javadevcentral.com/apache-commons-lang-pair/ In this post, we will learn about Apache Commons Lang Pair class. We use this class when we have a need to manage one or more pair of values. https://javadevcentral.com/apache-commons-text-wordutils/ Mon, 30 Aug 2021 14:02:00 +0530 https://javadevcentral.com/apache-commons-text-wordutils/ The Apache Commons Text WordUtils class has many static utility methods to perform operations on strings that contain words. https://javadevcentral.com/collectors-mapping-in-java/ Mon, 23 Aug 2021 13:56:00 +0530 https://javadevcentral.com/collectors-mapping-in-java/ Collectors mapping in Java is a static method in the Collectors class. In this post, we will learn about the mapping method in Collectors. https://javadevcentral.com/comparator-naturalorder-reverseorder-reversed/ Mon, 26 Jul 2021 12:26:00 +0530 https://javadevcentral.com/comparator-naturalorder-reverseorder-reversed/ As a follow up of the Comparator comparing post, here we will learn about the Comparator naturalOrder, reverseOrder and reversed methods. https://javadevcentral.com/static-utility-methods-in-objects/ Sun, 04 Jul 2021 12:20:00 +0530 https://javadevcentral.com/static-utility-methods-in-objects/ The Objects class has many useful static utility methods. In this post we will learn about the static utility methods in the Objects class. https://javadevcentral.com/functional-interfaces-in-java-functions/ Sun, 06 Jun 2021 12:11:00 +0530 https://javadevcentral.com/functional-interfaces-in-java-functions/ In this post, we will learn about the functional interface in Java for functions present as part of the java.util.function namespace. https://javadevcentral.com/optionalint-optionallong-and-optionaldouble/ Mon, 10 May 2021 12:03:00 +0530 https://javadevcentral.com/optionalint-optionallong-and-optionaldouble/ The OptionalInt, OptionalLong and OptionalDouble in Java are container objects which may contain a int, long and double value respectively. https://javadevcentral.com/stringtokenizer-in-java/ Mon, 19 Apr 2021 11:55:00 +0530 https://javadevcentral.com/stringtokenizer-in-java/ The StringTokenizer helps to break a string into tokens with a specified delimiter. In this post, we will learn about StringTokenizer in Java. https://javadevcentral.com/java-doublestream-a-complete-guide/ Mon, 05 Apr 2021 10:26:00 +0530 https://javadevcentral.com/java-doublestream-a-complete-guide/ A Java DoubleStream is a sequence of double-valued elements that supports sequential and parallel aggregate operations. https://javadevcentral.com/default-methods-in-java-map/ Mon, 22 Mar 2021 20:09:00 +0530 https://javadevcentral.com/default-methods-in-java-map/ Many JDK interfaces were enhanced with default methods in Java 8. In this post we will learn about the default methods in the Java Map interface. https://javadevcentral.com/apache-commons-lang-validate/ Tue, 16 Mar 2021 21:02:00 +0530 https://javadevcentral.com/apache-commons-lang-validate/ The Apache Commons Lang Validate class in the Apache Commons Lang library helps in validating arguments to a method (or a constructor) https://javadevcentral.com/apache-commons-lang-range/ Mon, 01 Mar 2021 21:54:00 +0530 https://javadevcentral.com/apache-commons-lang-range/ The Apache Commons Lang library provides utility classes and methods. In the post we will learn about the Apache Commons Lang Range class. https://javadevcentral.com/immutable-collections-using-collectors/ Mon, 22 Feb 2021 22:48:00 +0530 https://javadevcentral.com/immutable-collections-using-collectors/ In Java 10, the Collectors has static utility methods to return collectors which collect the stream elements into an immutable collection. https://javadevcentral.com/java-collections-utility-methods/ Mon, 15 Feb 2021 22:36:00 +0530 https://javadevcentral.com/java-collections-utility-methods/ In this post we will learn about the various Java Collections Utility methods that operate on collections or return collections. https://javadevcentral.com/collectors-collectingandthen/ Mon, 01 Feb 2021 22:29:00 +0530 https://javadevcentral.com/collectors-collectingandthen/ Collectors collectingAndThen returns a new Collector that adapts a passed Collector to perform a finishing transformation function. https://javadevcentral.com/apache-commons-lang-comparableutils/ Mon, 18 Jan 2021 18:27:00 +0530 https://javadevcentral.com/apache-commons-lang-comparableutils/ The Apache Commons Lang ComparableUtils has utility methods for translating a Comparable result into a boolean represented as a Predicate. https://javadevcentral.com/immutable-collections-in-google-guava/ Mon, 11 Jan 2021 18:21:00 +0530 https://javadevcentral.com/immutable-collections-in-google-guava/ Google Guava provides ways to create Immutable Collections. In this post, we will learn to create immutable collections using Google Guava. https://javadevcentral.com/enummap-in-java/ Tue, 29 Dec 2020 18:15:00 +0530 https://javadevcentral.com/enummap-in-java/ An EnumMap in Java is a specialized map implementation for use with enum type as the keys. In this post, we will learn EnumMaps in Java. https://javadevcentral.com/six-ways-to-convert-a-java-stream-to-a-list/ Mon, 14 Dec 2020 18:09:00 +0530 https://javadevcentral.com/six-ways-to-convert-a-java-stream-to-a-list/ In this post, we will see six ways to convert a Java stream to a List. You can extend these if you want to convert a stream to a Set as well. https://javadevcentral.com/java-8-longstream/ Tue, 08 Dec 2020 17:59:00 +0530 https://javadevcentral.com/java-8-longstream/ The Java 8 LongStream is a sequence of primitive long-valued elements and is a long primitive specialization of Stream. https://javadevcentral.com/collectors-joining-in-java-8/ Mon, 30 Nov 2020 17:49:00 +0530 https://javadevcentral.com/collectors-joining-in-java-8/ Collectors.joining returns a Collector which concatenates the stream elements separated by a delimiter, prefix and suffix in encounter order. https://javadevcentral.com/java-8-stringjoiner-with-examples/ Mon, 23 Nov 2020 17:39:00 +0530 https://javadevcentral.com/java-8-stringjoiner-with-examples/ Java 8 StringJoiner class can be used to build a sequence of characters that are separated by a configured delimiter, prefix and a suffix. https://javadevcentral.com/throw-checked-exceptions-in-java-streams/ Tue, 17 Nov 2020 13:34:00 +0530 https://javadevcentral.com/throw-checked-exceptions-in-java-streams/ This post shows 4 ways to throw checked exceptions in Java streams i.e., having a lambda expression that can throw checked exception(s). https://javadevcentral.com/java-stream-distinct-by-property/ Mon, 09 Nov 2020 13:27:00 +0530 https://javadevcentral.com/java-stream-distinct-by-property/ Java Streams has a distinct method which removes duplicates by object’s equal method. This post explains ways to apply distinct by a property. https://javadevcentral.com/java-stream-distinct/ Mon, 02 Nov 2020 12:15:00 +0530 https://javadevcentral.com/java-stream-distinct/ The Java Stream Distinct is a stateful intermediate operation which returns a new stream which has only the distinct elements in it. https://javadevcentral.com/java-8-findfirst-findany/ Mon, 26 Oct 2020 12:08:00 +0530 https://javadevcentral.com/java-8-findfirst-findany/ The Java 8 Streams has findFirst and findAny methods which will return the first element and an arbitrary element from a stream respectively. https://javadevcentral.com/prototype-design-pattern/ Mon, 19 Oct 2020 12:05:00 +0530 https://javadevcentral.com/prototype-design-pattern/ The Prototype Pattern specifies the kind of objects to create using a prototypical instance and create new objects by copying this prototype https://javadevcentral.com/flyweight-design-pattern/ Mon, 12 Oct 2020 11:49:00 +0530 https://javadevcentral.com/flyweight-design-pattern/ The Flyweight design pattern allows us to use sharing to support a large number of fine-grained objects efficiently in an application. https://javadevcentral.com/anymatch-allmatch-and-nonematch/ Mon, 05 Oct 2020 11:12:00 +0530 https://javadevcentral.com/anymatch-allmatch-and-nonematch/ This post is on the anyMatch, allMatch and noneMatch methods which are short-circuiting terminal operations on a Java Stream. https://javadevcentral.com/function-chaining-in-java/ Tue, 29 Sep 2020 11:00:00 +0530 https://javadevcentral.com/function-chaining-in-java/ A Function is primarily used along with the map operation on a Java stream. In this post, we will learn about Function chaining in Java 8. https://javadevcentral.com/predicate-chaining-in-java/ Mon, 21 Sep 2020 10:52:00 +0530 https://javadevcentral.com/predicate-chaining-in-java/ We have used a Predicate in a Java stream. This post covers the methods in Predicate class which allow us to do Predicate chaining in Java 8. https://javadevcentral.com/apache-commons-cli/ Mon, 14 Sep 2020 10:37:00 +0530 https://javadevcentral.com/apache-commons-cli/ The Apache Commons CLI is a library that provides API for parsing command-line options/arguments which we pass to programs. https://javadevcentral.com/java-stream-takewhile-and-dropwhile/ Mon, 07 Sep 2020 22:08:00 +0530 https://javadevcentral.com/java-stream-takewhile-and-dropwhile/ The Java Stream takeWhile and dropWhile methods allow to return or drop a prefix/subset of elements in a stream based on a passed predicate. https://javadevcentral.com/seven-ways-to-create-a-stream-in-java/ Mon, 31 Aug 2020 12:05:00 +0530 https://javadevcentral.com/seven-ways-to-create-a-stream-in-java/ A Stream is a sequence of elements supporting sequential and parallel aggregate operations. We will see seven ways to create a Stream in Java https://javadevcentral.com/state-design-pattern/ Tue, 25 Aug 2020 22:46:00 +0530 https://javadevcentral.com/state-design-pattern/ The State Design Pattern allows an object to alter its behavior when its internal state changes. The object will appear to change its class. https://javadevcentral.com/apache-commons-fileutils-directory-operations/ Mon, 17 Aug 2020 22:35:00 +0530 https://javadevcentral.com/apache-commons-fileutils-directory-operations/ Apache Commons FileUtils has utility methods for file and directory manipulation. This post is on Apache Commons IO FileUtils directory operations. https://javadevcentral.com/apache-commons-fileutils-file-operations/ Mon, 10 Aug 2020 22:23:00 +0530 https://javadevcentral.com/apache-commons-fileutils-file-operations/ Apache Commons FileUtils has utility methods for file and directory manipulation. This post is on Apache Commons FileUtils file manipulation https://javadevcentral.com/collectors-minby-and-maxby/ Mon, 03 Aug 2020 19:54:00 +0530 https://javadevcentral.com/collectors-minby-and-maxby/ Collectors minBy and maxBy return a Collector that produces the minimal and maximal element according to a given Comparator https://javadevcentral.com/comparator-nullsfirst-and-nullslast/ Mon, 27 Jul 2020 18:41:00 +0530 https://javadevcentral.com/comparator-nullsfirst-and-nullslast/ Comparator nullsFirst and nullsLast methods returns a null-friendly comparator. It considers null to be less than or greater than any non-null value. https://javadevcentral.com/summary-statistics-in-java-8/ Mon, 20 Jul 2020 18:31:00 +0530 https://javadevcentral.com/summary-statistics-in-java-8/ Java 8 added three Summary Statistics classes viz., IntSummaryStatistics LongSummaryStatistics and DoubleSummaryStatistics used to collect statistics. https://javadevcentral.com/apache-commons-ioutils/ Tue, 14 Jul 2020 18:19:00 +0530 https://javadevcentral.com/apache-commons-ioutils/ The Apache Commons IO has utilities to help with various IO functionalities. In this post, we will see about the Apache Commons IO IOUtils class. https://javadevcentral.com/priority-queue-in-java/ Mon, 06 Jul 2020 18:09:00 +0530 https://javadevcentral.com/priority-queue-in-java/ A Priority Queue is an unbounded queue based on a priority heap. The elements are ordered according to their natural ordering or by a Comparator provided. https://javadevcentral.com/bridge-design-pattern/ Mon, 29 Jun 2020 18:01:00 +0530 https://javadevcentral.com/bridge-design-pattern/ The Bridge Design Pattern decouples an abstraction from its implementation so that the two can vary independently. This pattern is also known as Handle/Body. https://javadevcentral.com/collectors-partitioningby-in-java/ Mon, 22 Jun 2020 17:05:00 +0530 https://javadevcentral.com/collectors-partitioningby-in-java/ The Collectors partitioningBy method in the Collectors class groups the elements of a stream by a predicate and an optional downstream collector https://javadevcentral.com/java-stream-sum/ Mon, 15 Jun 2020 16:56:00 +0530 https://javadevcentral.com/java-stream-sum/ In this post, we will see the three ways to sum a stream of numbers (using Java streams). We use the mapToInt, reduce, and collect methods. https://javadevcentral.com/composite-design-pattern/ Mon, 08 Jun 2020 16:46:00 +0530 https://javadevcentral.com/composite-design-pattern/ The Composite Design Pattern composes objects into tree structures to represent part-whole hierarchies and lets clients treat individual objects and compositions of objects uniformly. https://javadevcentral.com/collectors-new-methods-jdk-9-to-11/ Mon, 01 Jun 2020 16:36:00 +0530 https://javadevcentral.com/collectors-new-methods-jdk-9-to-11/ In this post, we will learn about the new methods added to the Java Collectors from Java 9 to 11 (Collectors filtering, flatMapping and teeing). https://javadevcentral.com/default-method-resolution-rules/ Mon, 25 May 2020 16:24:00 +0530 https://javadevcentral.com/default-method-resolution-rules/ This post covers the default method resolution rules. These will be used when a class inherits more than one method with the same signature. https://javadevcentral.com/files-walk-file-tree/ Mon, 18 May 2020 16:09:00 +0530 https://javadevcentral.com/files-walk-file-tree/ The Files.walkFileTree static method from the NIO Files class is used to walk a file tree. The walk traverses the directory tree in a depth-first order. https://javadevcentral.com/java-nio-files-part-2/ Mon, 11 May 2020 15:51:00 +0530 https://javadevcentral.com/java-nio-files-part-2/ The Java NIO Files class has static utility methods that operate on files and directories. In this post, we learn about the common operations on directories https://javadevcentral.com/java-nio-files-part-1/ Tue, 05 May 2020 15:33:00 +0530 https://javadevcentral.com/java-nio-files-part-1/ The Java NIO Files class has static utility methods that operate on files and directories. This post covers the NIO operations on files. https://javadevcentral.com/convenience-factory-methods-for-collections/ Mon, 27 Apr 2020 11:39:00 +0530 https://javadevcentral.com/convenience-factory-methods-for-collections/ Java 9 introduced the Convenience Factory Methods for Collections that make it convenient to create instances of collections or maps with few elements https://javadevcentral.com/preconditions-in-google-guava/ Tue, 21 Apr 2020 11:20:00 +0530 https://javadevcentral.com/preconditions-in-google-guava/ Preconditions in the Google Guava offers static utility methods that will help us write one-line statements for doing precondition validations. https://javadevcentral.com/measuring-elapsed-time-using-a-stopwatch/ Mon, 13 Apr 2020 17:08:00 +0530 https://javadevcentral.com/measuring-elapsed-time-using-a-stopwatch/ This post is about measuring elapsed time in Java using a Stopwatch. We will over cover the Stopwatch from Google Guava and the Apache Commons lang. https://javadevcentral.com/default-methods-in-java/ Mon, 06 Apr 2020 10:53:00 +0530 https://javadevcentral.com/default-methods-in-java/ Default methods in Java enable us to add new functionality to the interfaces of our libraries without breaking the existing implementations of the interface https://javadevcentral.com/listiterator-in-java-with-examples/ Mon, 30 Mar 2020 15:36:00 +0530 https://javadevcentral.com/listiterator-in-java-with-examples/ A ListIterator in Java is an Iterator that allows us to traverse the list in either direction, modify the list during iteration, and obtain the iterator’s current position in the list. https://javadevcentral.com/mediator-design-pattern/ Mon, 23 Mar 2020 21:46:00 +0530 https://javadevcentral.com/mediator-design-pattern/ Mediator Design Pattern defines an object that encapsulates how a set of objects interact and keeps the objects from referring to each other explicitly. https://javadevcentral.com/bimap-in-google-guava/ Tue, 17 Mar 2020 13:36:00 +0530 https://javadevcentral.com/bimap-in-google-guava/ The BiMap in Google Guava is a bidirectional map that preserves the uniqueness of values and keys. This allows us to lookup by value in the map too. https://javadevcentral.com/memento-design-pattern/ Mon, 09 Mar 2020 21:26:00 +0530 https://javadevcentral.com/memento-design-pattern/ The Memento Design Pattern allows to capture and externalize an object’s internal state so that the object can be restored later without violating encapsulation https://javadevcentral.com/effective-java-builder-pattern/ Mon, 02 Mar 2020 22:19:00 +0530 https://javadevcentral.com/effective-java-builder-pattern/ Introduction In the last post, I wrote about the Gang of Four (GoF) Builder Design Pattern. In this post, we will look at the builder pattern from the Effective Java… https://javadevcentral.com/builder-design-pattern/ Tue, 25 Feb 2020 21:09:00 +0530 https://javadevcentral.com/builder-design-pattern/ The builder design pattern separates the construction of an object from its representation so that the same process can create different representations. https://javadevcentral.com/multimap-in-google-guava/ Tue, 18 Feb 2020 20:55:00 +0530 https://javadevcentral.com/multimap-in-google-guava/ A Multimap is a map but it can map multiple values against a key. In this post, we will look at a related class of Multiset - the Multimap in Google Guava. https://javadevcentral.com/chain-of-responsibility/ Tue, 11 Feb 2020 20:42:00 +0530 https://javadevcentral.com/chain-of-responsibility/ The chain of responsibility design pattern chains the receiving objects and pass the request along the chain until an object handles it. https://javadevcentral.com/multiset-in-google-guava/ Tue, 04 Feb 2020 21:25:00 +0530 https://javadevcentral.com/multiset-in-google-guava/ A Multiset in Google Guava is a collection that supports order-independent equality (behaves like a Set). But it can have duplicate elements. https://javadevcentral.com/jmh-benchmark-with-examples/ Tue, 28 Jan 2020 14:12:00 +0530 https://javadevcentral.com/jmh-benchmark-with-examples/ JMH (Java Microbenchmark Harness) is a Java harness library for writing benchmarks on the JVM. In this post, we will learn about JVM benchmark. https://javadevcentral.com/java-8-streams-are-not-completely-lazy/ Mon, 20 Jan 2020 20:45:00 +0530 https://javadevcentral.com/java-8-streams-are-not-completely-lazy/ Java 8 streams are lazy. The intermediate operations will not be executed till a terminal operation is invoked. But, Java 8 streams flatMap are not lazy. https://javadevcentral.com/facade-design-pattern/ Wed, 15 Jan 2020 20:35:00 +0530 https://javadevcentral.com/facade-design-pattern/ The Facade Design Pattern provides a unified interface to a set of interfaces in a subsystem. It defines a higher level interface that makes the subsystem easier to use. https://javadevcentral.com/enumeration-and-iterator-in-java/ Tue, 07 Jan 2020 20:22:00 +0530 https://javadevcentral.com/enumeration-and-iterator-in-java/ Java has two ways to iterate over the elements of a collection - using an Enumeration and an Iterator. This post explains Enumeration and Iterators in Java. https://javadevcentral.com/adapter-design-pattern/ Mon, 30 Dec 2019 19:01:00 +0530 https://javadevcentral.com/adapter-design-pattern/ The Adapter Design Pattern converts an interface into another interface that the clients expect. It adapts an interface to look like a different interface. https://javadevcentral.com/write-csv-files-using-apache-commons-csv/ Tue, 24 Dec 2019 17:48:00 +0530 https://javadevcentral.com/write-csv-files-using-apache-commons-csv/ Apache Commons CSV is one of the components in the Apache Commons project. This post is on how to write CSV files using Apache Commons CSV. https://javadevcentral.com/naive-benchmarking-framework-in-java/ Mon, 16 Dec 2019 18:33:00 +0530 https://javadevcentral.com/naive-benchmarking-framework-in-java/ In this post, let us build on our previous benchmarking attempt to arrive at a better but still a naive benchmarking framework in Java. https://javadevcentral.com/measuring-execution-time-the-wrong-way/ Tue, 10 Dec 2019 17:26:00 +0530 https://javadevcentral.com/measuring-execution-time-the-wrong-way/ In this post, I explain the usual way in measuring the execution or running time of code in Java, what is wrong with it and why it shouldn’t be used. https://javadevcentral.com/collectors-tomap-duplicate-key/ Mon, 02 Dec 2019 16:40:00 +0530 https://javadevcentral.com/collectors-tomap-duplicate-key/ This post shows the Collectors toMap duplicate key exception and the changes made in Java 9 to improve the exception message to contain the value of the key. https://javadevcentral.com/template-method-design-pattern/ Mon, 25 Nov 2019 19:50:00 +0530 https://javadevcentral.com/template-method-design-pattern/ The Template Method Design Pattern defines the steps of an algorithm and allows subclasses to provide the implementation for one or more steps. https://javadevcentral.com/optional-new-methods/ Mon, 18 Nov 2019 15:34:00 +0530 https://javadevcentral.com/optional-new-methods/ Optional was added to Java 8. This post explains the new methods or APIs added to the Optional class in Java from Java 9 through 11 with examples. https://javadevcentral.com/a-complete-guide-to-java-optional/ Mon, 11 Nov 2019 14:49:00 +0530 https://javadevcentral.com/a-complete-guide-to-java-optional/ Optional is a container object added to Java 8+ that is used as a wrapper over some value. It provides a mechanism to represent “no result” for a method. https://javadevcentral.com/proxy-pattern-vs-decorator-pattern/ Mon, 04 Nov 2019 14:34:00 +0530 https://javadevcentral.com/proxy-pattern-vs-decorator-pattern/ This post explores the differences between the Proxy Design Pattern and the Decorator Design Pattern. https://javadevcentral.com/proxy-design-pattern/ Sun, 27 Oct 2019 14:24:00 +0530 https://javadevcentral.com/proxy-design-pattern/ The Proxy Design Pattern provides a surrogate or placeholder for another object to control access to it. It acts as a stand-in for another object. https://javadevcentral.com/decorator-design-pattern/ Wed, 23 Oct 2019 13:19:00 +0530 https://javadevcentral.com/decorator-design-pattern/ The Decorator design pattern attaches additional responsibilities to an object dynamically. It is an alternative to subclassing for extending functionality. https://javadevcentral.com/three-ways-to-sort-a-list-in-java/ Sun, 13 Oct 2019 12:27:00 +0530 https://javadevcentral.com/three-ways-to-sort-a-list-in-java/ In this blog post, we will see three ways to sort a list in Java. We will see how to sort in ascending and in reversed order. https://javadevcentral.com/collectors-groupingby-with-examples/ Sun, 06 Oct 2019 13:16:00 +0530 https://javadevcentral.com/collectors-groupingby-with-examples/ The Collectors groupingBy is a static utility method in the Collectors class. It is used to group the stream elements by a key. In this blog post, we will look at the Collectors groupingBy with examples. https://javadevcentral.com/java-8-collectors-tomap-with-examples/ Sun, 29 Sep 2019 12:03:00 +0530 https://javadevcentral.com/java-8-collectors-tomap-with-examples/ In this blog post, I will demonstrate the Java 8 Collectors.toMap method with examples and how it’s used to fold a stream into a map. https://javadevcentral.com/google-guava-iterators/ Mon, 23 Sep 2019 11:46:00 +0530 https://javadevcentral.com/google-guava-iterators/ Google Guava is a Java library belonging to the Guava project of Google. In this post, we will look at the Google Guava Iterators utility class. https://javadevcentral.com/observer-pattern-using-java-observable/ Mon, 16 Sep 2019 10:22:00 +0530 https://javadevcentral.com/observer-pattern-using-java-observable/ The Observer Design Pattern enables the subject to notify its observers when its state changes. In this post, we implement it using Java’s Observable class. https://javadevcentral.com/observer-design-pattern/ Mon, 26 Aug 2019 11:10:00 +0530 https://javadevcentral.com/observer-design-pattern/ The Observer Design Pattern defines a one-to-many dependency between objects so that when the subject’s changes state, all of its observers are notified. https://javadevcentral.com/joiner-in-google-guava/ Tue, 20 Aug 2019 14:02:00 +0530 https://javadevcentral.com/joiner-in-google-guava/ Google Guava is a Java library belonging to the Guava project of Google. We will look at the Joiner Utility class in the Google Guava library. https://javadevcentral.com/string-utilities-in-google-guava/ Wed, 14 Aug 2019 16:49:00 +0530 https://javadevcentral.com/string-utilities-in-google-guava/ Google Guava belongs to the Guava project of Google. The String Utilities in Google Guava library offers several helper methods for working with Strings. https://javadevcentral.com/enumset-in-java/ Tue, 06 Aug 2019 10:41:00 +0530 https://javadevcentral.com/enumset-in-java/ An EnumSet in Java is a specialized Set implementation meant to be used with enum types. All the elements in an EnumSet are enum instances. https://javadevcentral.com/treemap-in-java/ Wed, 31 Jul 2019 15:31:00 +0530 https://javadevcentral.com/treemap-in-java/ A TreeMap is a Red-Black Tree based implementation of a NavigableMap. In this post, we will look at TreeMap in Java and the methods offered by them. https://javadevcentral.com/how-hashmap-works-in-java/ Mon, 22 Jul 2019 19:39:00 +0530 https://javadevcentral.com/how-hashmap-works-in-java/ A Map data structure is an object that maps keys to values. We will see how a HashMap works in java. We will also see how get and put operations work. https://javadevcentral.com/iterator-design-pattern/ Mon, 15 Jul 2019 17:22:00 +0530 https://javadevcentral.com/iterator-design-pattern/ The Iterator Design Pattern provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation. https://javadevcentral.com/benefits-of-immutable-class-in-java/ Sat, 29 Jun 2019 17:12:00 +0530 https://javadevcentral.com/benefits-of-immutable-class-in-java/ An immutable class is a class whose instances cannot be modified after it is created. In this post, we will look at the benefits of immutable class in Java. https://javadevcentral.com/how-to-make-a-class-immutable-in-java/ Tue, 25 Jun 2019 20:40:00 +0530 https://javadevcentral.com/how-to-make-a-class-immutable-in-java/ An immutable class is one that does not change its state after its construction. In this post, we will learn how to make a class immutable. https://javadevcentral.com/read-csv-files-using-apache-commons-csv/ Mon, 17 Jun 2019 16:30:00 +0530 https://javadevcentral.com/read-csv-files-using-apache-commons-csv/ The Apache Commons CSV can be used for reading and writing Comma Separated Value (CSV) files. It is part of the Apache Commons project. https://javadevcentral.com/checked-and-unchecked-exception-in-java/ Sun, 09 Jun 2019 18:20:00 +0530 https://javadevcentral.com/checked-and-unchecked-exception-in-java/ Checked exceptions are checked at compile time whereas unchecked exceptions are not. Unchecked exceptions generally denote programming errors. https://javadevcentral.com/java-method-references/ Wed, 29 May 2019 18:05:00 +0530 https://javadevcentral.com/java-method-references/ A method reference is a reference to an existing method. When a lambda expression just calls an existing method, we can use a Method Reference. https://javadevcentral.com/java8-intstream/ Tue, 14 May 2019 17:42:00 +0530 https://javadevcentral.com/java8-intstream/ A sequence of primitive int-valued elements supporting sequential and parallel and aggregate operations. It is an int primitive specialization of Stream. https://javadevcentral.com/java-comparator-comparing/ Mon, 29 Apr 2019 16:23:00 +0530 https://javadevcentral.com/java-comparator-comparing/ The Comparator is a comparison function in Java that imposes a total ordering on a collection of objects. The comparing is a static method in it https://javadevcentral.com/rxjava-observable/ Sat, 16 Mar 2019 15:16:00 +0530 https://javadevcentral.com/rxjava-observable/ An RxJava Observable supports emitting a sequence of items. An Observer subscribes to an Observable. The Observer reacts to the items the Observable emits. https://javadevcentral.com/introduction-to-rxjava/ Sun, 10 Mar 2019 19:32:00 +0530 https://javadevcentral.com/introduction-to-rxjava/ RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM. https://javadevcentral.com/abstract-factory-pattern/ Sat, 16 Feb 2019 19:07:00 +0530 https://javadevcentral.com/abstract-factory-pattern/ The Abstract Factory Pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes. https://javadevcentral.com/factory-method/ Tue, 15 Jan 2019 17:10:00 +0530 https://javadevcentral.com/factory-method/ Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses. https://javadevcentral.com/strategy-design-pattern/ Mon, 10 Dec 2018 19:05:00 +0530 https://javadevcentral.com/strategy-design-pattern/ Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it. https://javadevcentral.com/privacy-policy/ Mon, 29 Oct 2018 19:10:00 +0530 https://javadevcentral.com/privacy-policy/ The Privacy Policy page https://javadevcentral.com/about/ Mon, 29 Oct 2018 19:05:00 +0530 https://javadevcentral.com/about/ The about page