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Java Articles
Page 245 of 450
Calling a method using null in Java\\n
When a method is invoked on a null reference, it throws NullPointerException but in case of the static method, we can make it possible using cast expression. See the example below −ExampleLive Demopublic class Tester { public static void display(){ System.out.println("display"); } private void print() { System.out.println("print"); } public static void main(String[] args) { //Scenario 1: //Calling a method on null reference //causes NullPointerException try { Tester test = null; ...
Read MoreCalling a method using null in Java\\n
When a method is invoked on a null reference, it throws NullPointerException but in case of the static method, we can make it possible using cast expression. See the example below −ExampleLive Demopublic class Tester { public static void display(){ System.out.println("display"); } private void print() { System.out.println("print"); } public static void main(String[] args) { //Scenario 1: //Calling a method on null reference //causes NullPointerException try { Tester test = null; ...
Read MoreAutomatic resource management in Java\\n
automatic resource management or try-with-resources is a new exception handling mechanism that was introduced in Java 7, which automatically closes the resources used within the try-catch block.ResourceA resource is an object which is required to be closed once our program finishes. For example, a file is read, database connection and so on.UsageTo use the try-with-resources statement, you simply need to declare the required resources within the parenthesis, and the created resource will be closed automatically at the end of the block. Following is the syntax of the try-with-resources statement.Syntaxtry(FileReader fr = new FileReader("file path")) { // use the resource ...
Read MoreAutomatic resource management in Java\\n
automatic resource management or try-with-resources is a new exception handling mechanism that was introduced in Java 7, which automatically closes the resources used within the try-catch block.ResourceA resource is an object which is required to be closed once our program finishes. For example, a file is read, database connection and so on.UsageTo use the try-with-resources statement, you simply need to declare the required resources within the parenthesis, and the created resource will be closed automatically at the end of the block. Following is the syntax of the try-with-resources statement.Syntaxtry(FileReader fr = new FileReader("file path")) { // use the resource ...
Read MoreAddition and Concatenation in Java
'+' operator in java can be used to add numbers and concatenate strings. Following rules should be considered.Only numbers as operands then result will be a number.Only strings as operands then result will be a concatenated string.If both numbers and strings as operands, then numbers coming before string will be treated as numbers.If both numbers and strings as operands, then numbers coming after string will be treated as a string.Above rule can be overridden using brackets().ExampleCreate a java class named Tester.Tester.javaLive Demopublic class Tester { public static void main(String args[]) { //Scenario 1: ...
Read MoreFactorial program in Java without using recursion.
Following is the required program.ExampleLive Demopublic class Tester { static int factorial(int n) { if (n == 0) return 1; else return (n * factorial(n - 1)); } public static void main(String args[]) { int i, fact = 1; int number = 5; fact = factorial(number); System.out.println(number + "! = " + fact); } }Output5! = 120
Read MoreFactorial program in Java without using recursion.
Following is the required program.ExampleLive Demopublic class Tester { static int factorial(int n) { if (n == 0) return 1; else return (n * factorial(n - 1)); } public static void main(String args[]) { int i, fact = 1; int number = 5; fact = factorial(number); System.out.println(number + "! = " + fact); } }Output5! = 120
Read MoreWhat are the 6 ways to use this keyword in Java?
this can be used to get the current object.this can be used to invoke current object's method.this() can be used to invoke current class constructorthis can be passed as a parameter to a method call.this can be passed as a parameter to a constructor.this can be used to return the current object from the method.
Read MoreWhat are the 6 ways to use this keyword in Java?
this can be used to get the current object.this can be used to invoke current object's method.this() can be used to invoke current class constructorthis can be passed as a parameter to a method call.this can be passed as a parameter to a constructor.this can be used to return the current object from the method.
Read MoreJava (JVM) Memory Types
Java Virtual Machine is a program/software which takes Java bytecode (.class files)and converts the byte code (line by line) into machine understandable code.JVM contains a module known as a class loader. A class loader in JVM loads, links and, initializes a program. It−Loads the class into the memory. Verifies the byte code instructions.Allocates memory for the program.The memory in the JVM is divided into five different parts namely− Method area− The method area stores the class code − code of the variables and methods. Heap − The Java objects are created in this area. Java Stack− While running methods the results are stored in ...
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