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Java Articles
Page 295 of 450
How many ways to iterate a LinkedList in Java?
A LinkedList is a data structure that contains a group of nodes connected in a sequential manner with a pointer. A LinkedList can behave as a dynamic array and it allocates space for each element separately in its own block of memory called a Node. Each node contains two fields, a "data" field to store an element type the list holds and a "next" field which is a pointer used to link one node to the next node.We can iterate the elements of a LinkedList in three ways in Java.Using IteratorWe can iterate the elements of a LinkedList through the ...
Read MoreWhat is the default value of a local variable in Java?
The local variables can be declared in methods, code blocks, constructors, etc in Java. When the program control enters the methods, code blocks, constructors, etc. then the local variables are created and when the program control leaves the methods, code blocks, constructors, etc. then the local variables are destroyed. The local variables do not have any default values in Java. This means that they can be declared and assigned a value before the variables are used for the first time, otherwise, the compiler throws an error.Examplepublic class LocalVariableTest { public void print() { ...
Read MoreHow can we add padding to a JTextField in Java?
A JTextField is a subclass of JTextComponent class and it is one of the most important components that allow the user to input text value in a single-line format. A JTextField class will generate an ActionListener interface when we trying to enter some input inside it. The important methods of a JTextField class are setText(), getText(), setBorder(), setEnabled(), etc. We can add padding to a JTextField using the setMargin(Insets s) of JTextComponent class.Syntaxpublic void setMargin(Insets m)Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class JTextfieldPaddingTest extends JFrame { private JTextField jtf; public JTextfieldPaddingTest() { ...
Read MoreHow to set the color to alternate rows of JTable in Java?
A JTable is a subclass of JComponent class and it can be used to create a table with information displayed in multiple rows and columns. When a value is selected from a JTable, a TableModelEvent is generated, which is handled by implementing a TableModelListener interface.We can set the color to alternate rows of JTable by overriding the prepareRenderer() method of JTable class.Syntaxpublic Component prepareRenderer(TableCellRenderer renderer, int row, int column)Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.table.*; public class AlternateRowColorTableTest extends JFrame { public AlternateRowColorTableTest() { setTitle("AlternateRowColorTable Test"); ...
Read MoreWhile chaining, can we throw unchecked exception from a checked exception in java?
When an exception is cached in a catch block, you can re-throw it using the throw keyword (which is used to throw the exception objects).While re-throwing exceptions you can throw the same exception as it is with out adjusting it as −try { int result = (arr[a])/(arr[b]); System.out.println("Result of "+arr[a]+"/"+arr[b]+": "+result); }catch(ArithmeticException e) { throw e; }Or, wrap it within a new exception and throw it. When you wrap a cached exception within another exception and throw it, it is known as exception chaining or, exception wrapping, by doing this you can adjust your exception, throwing higher ...
Read MoreWhen can a .class file get created in Java?
A Java class file has a ".class" extension and contains the Java bytecode. This class file can be executed by the Java Virtual Machine (JVM). A ".class" file is created as a result of successful compilation by the Java compiler from the ".java" file. Each class in the .java file is compiled into a separate class file if the ".java " file has more than one class.Exampleclass A { A() { System.out.println("This is class A"); } } class B { B() { ...
Read MoreIs there any method to convert a Set to immutable in Java
Whenever you need to create an object which cannot be changed after initialization you can define an immutable object. There are no specific rules to create immutable objects, the idea is to restrict the access of the fields of a class after initialization.A Set is an interface in collection framework, which does not allow duplicate values.Method to convert a set to immutableYes, Java provides a method named unmodifiableSet() in the Collections class. This method accepts a collection object as a parameter and returns an unmodifiable i.ie immutable form of it.ExampleIn the following Java program, we have created a HashSet object ...
Read MoreHow can we check an underflow occurs in Java?
When a value is assigned to a variable that is less than the minimum allowed value for that variable, then an underflow occurs. There is no exception thrown by the JVM if an underflow occurs in Java and it is the responsibility of a programmer to handle the underflow conditions.Examplepublic class UnderlowTest { public static void main(String[] args) { int num1 = -2147483648; int num2 = -1; System.out.println("Number 1: " + num1); System.out.println("Number ...
Read MoreWhy TreeSet Does not allow null values in Java?
TreeSet provides an implementation of the Set interface that uses a tree for storage. Objects are stored in a sorted and ascending order.Access and retrieval times are quite fast, which makes TreeSet an excellent choice when storing large amounts of sorted information that must be found quickly.The reason is, if you look at the internal implementation of the TreeSet, it uses natural ordering, that means TreeSet uses Comparable interface by default to sort its value by comparing other value.Examplepublic class TreeSetDemo { public static void main(String args[]) { TreeSet treeSet = new TreeSet(); ...
Read MoreHow to convert an array to Set and vice versa in Java?
Array is a container which can hold a fix number of entities, which are of the same type. Each entity of an array is known as element and, the position of each element is indicated by an integer (starting from 0) value known as index.Exampleimport java.util.Arrays; public class ArrayExample { public static void main(String args[]) { Number integerArray[] = new Integer[3]; integerArray[0] = 25; integerArray[1] = 32; integerArray[2] = 56; System.out.println(Arrays.toString(integerArray)); } }Output[25, 32, 56]Whereas a Set object is a collection (object) stores ...
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