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Java Articles
Page 162 of 450
What are the differences between paint() method and repaint() method in Java?
In this article, we will learn about the differences between the paint() method and the repaint() method in Java. In the AWT and Swing frameworks, rendering graphical components is done in two different roles by the two methods paint() and repaint(). The paint() Method This method holds instructions to paint this component. In Java Swing, we can change the paintComponent() method instead of paint() method as paint calls paintBorder(), paintComponent() and paintChildren() methods. We cannot call this method directly instead we can call repaint(). Syntax The following is the syntax: public void paint(Graphics g) { // paint() method ...
Read MoreHow can we minimize/maximize a JFrame programmatically in Java?
In this article, we will learn to minimize/maximize a JFrame programmatically in Java. In Swing, programmers often need to resize the window as needed. For example, they can shrink the window when carrying out background tasks or expand the window size for a better full-screen experience. What is a JFrame? A JFrame class is a subclass of Frame class and the components added to a frame are referred to as its contents, these are managed by the contentPane. A JFrame contains a window with title, border, (optional) menu bar and user-specific components. By default, we can minimize a JFrame by ...
Read MoreDifference between Stack and Heap memory in Java
JVM has divided memory space between two parts: one is Stack and another one is Heap space. Stack space is mainly used for storing order of method execution and local variables. Stacks always store blocks in LIFO order whereas heap memory uses dynamic allocation for allocating and deallocating memory blocks. Memory allocated to the heap lives until one of the following events occurs : Program terminated Memory free What is a Heap memory? Heap memory is allocated for storing objects, arrays, and JRE (Java Runtime Environment) classes. Memory may be ...
Read MoreDifference Between ReentrantLock and Synchronized in Java
There are two ways to get a lock on the shared resource by multiple threads. One is a Reentrant Lock (or read/write lock), and the other is by using the Synchronized method. The reentrant lock class has been provided in the Java concurrency package from Java 5. It is the implementation of the Lock interface, and according to Java docs, the implementation of the Lock interface provides more extensive operation than can be obtained using synchronized method. What is the Reentrant lock? ReetrantLock is a class that implements the Lock Interface. It provides the synchronization feature with great flexibility, ...
Read MoreDifference between Serialization and Externalization in Java
Serialization and externalization both are the processes of converting an object to stream byte and storing byte stream in database or memory. The class that implements java.io.Serializable interface can be serialized. What is Serialization? Java provides a mechanism called object serialization where an object can be converted into a byte stream that includes the object's data and details about the object's type. Example The following is an example of Serialization in Java: import java.io.Serializable; class SerializableExample implements Serializable { private static final long serialVersionUID = 5081877L; String name; } public ...
Read MoreDifference between Concurrent hash map and Synchronized hashmap in Java
A Map is an object that stores key-value pairs, where each key is unique but values can repeat. The HashMap is a type of Map that uses a hashtable in order to store these pairs. Now we will discuss the differences between ConcurrentHashMap and Synchronized Hashmap. What is a ConcurrentHashMap? ConcurrentHashMap is a class that was introduced in jdk1.5. ConcurrentHashMap applies locks only at bucket level called fragment while adding or updating the map. So, aConcurrentHashMap allows concurrent read and write operation to the map. Example of ConcurrentHashMap The following is an example of ConcurrentHashMap in java − import java.util.Map; ...
Read MoreDifference between Comparable and Comparator in Java
Comparable and Comparator both are an interface that can be used to sort the elements of the collection. Comparator interface belongs to java.util package while comparable belongs to java.lang package. Comparator interface sort collection using two objects provided to it, whereas comparable interface compares" this" refers to the one objects provided to it. What is a Comparable interface? The Comparable interface is an interface which is used by Java Collections to sort and compare custom objects. It belongs to java.lang package and has a single method called compareTo(). Example of Comparable The following is an example of Comparable in ...
Read MoreWhat is the importance of a Cursor class in Java?
In this article, we will learn about the importance of the Cursor class in Java. Under the Swing toolkit, the Cursor class provides an improved user experience by providing graphical(visual) feedback. What is a Cursor class? A Cursor is a subclass of the Object class, and it can be defined as point or indicator on the screen. A Cursor is used to select the input from the system that the user operates with the mouse. The important methods of Cursor class are getDefaultCursor(), getName(), getPredefinedCursor(), getSystemCustomCursor(), and getType(). Syntax The following is the syntax: Cursor cursor = new Cursor(Type_of_Cursor); Different ...
Read MoreDifference between Tree Set and Hash Set in Java
In Java, HashSet and TreeSet both belong to the collection framework. HashSet is the implementation of the Set interface, whereas TreeSet implements a sorted set. TreeSet is backed by TreeMap while HashSet is backed by a HashMap. Difference Table The following are the key differences between HashSet and TreeSet : Sr. No. Key ...
Read MoreJava program to compare two sets
The given task is to write Java programs that compare two sets and check if they are equal or not. Here, Set is an interface of the Java Collection Framework that extends the Collection interface and stores unique elements. Set depicts the features of a mathematical set. Hence, it allows all those operations that we can perform on a mathematical set, such as union, comparison, intersection, etc. Since Set is an interface, we can't use its functionalities directly. For this purpose, we need a TreeSet class that implements the Set Interface and can access its methods. How to Compare Two Sets in ...
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