JAVA TUTORIALS FOR BEGINNER: concept

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Java
 methods tutorial: Java program consists of one or more classes and a 
class may contain method(s). 
 A class can do very little without methods.
 In this tutorial we will learn about Java methods. Methods are known as
 functions in C and C++ programming languages. A method has a name and 
return type. Main method is a must in a Java program as execution begins
 from it.

<h2>
Syntax of methods</h2>
"Access specifier" "Keyword(s)" "return type" methodName(List of arguments) { 
 // Body of method 
}

Access specifier can be public or private which decides whether other classes can call a method. 
Kewords are used for some special methods such as static or synchronized. 
Return type indicate return value which method returns. 
Method name is a valid Java identifier name.

Access specifier, Keyword and arguments are optional.

Examples of methods declaration: 
public static void main(String[] args); 
void myMethod(); 
private int maximum(); 
public synchronized int search(java.lang.Object);

<h2>
Java Method example program</h2>
<div class="geshifilter">
<pre class="java geshifilter-java" style="font-family: monospace;">class Methods {
 
 // Constructor method
 
 Methods() {
 System.out.println("Constructor method is called when an object of it's class is created");
 }
 
 // Main method where program execution begins
 
 public static void main(String[] args) {
 staticMethod();
 Methods object = new Methods();
 object.nonStaticMethod();
 }
 
 // Static method
 
 static void staticMethod() {
 System.out.println("Static method can be called without creating object");
 }
 
 // Non static method
 
 void nonStaticMethod() {
 System.out.println("Non static method must be called by creating an object");
 }
}</pre>
</div>
Output 
 
 
<img alt="Java methods program output" src="http://www.programmingsimplified.com/images/java/methods-java.png" />

<h2>
Java methods list</h2>
Java has a built in library of many useful classes and there are 
thousands of methods which can be used in your programs. Just call a 
method and get your work done :) . You can find list of methods in a 
class by typing following command on command prompt:

javap package.classname

For example 
javap java.lang.String // list all methods and constants of String class. 
javap java.math.BigInteger // list constants and methods of BigInteger class in java.math package

<h2>
Java String methods</h2>
String class contains methods which are useful for performing 
operations on String(s). Below program illustrate how to use inbuilt 
methods of String class.

<h3>
Java string class program</h3>
<div class="geshifilter">
<pre class="java geshifilter-java" style="font-family: monospace;">class StringMethods
{
 public static void main(String args[])
 {
 int n;
 String s = "Java programming", t = "", u = "";
 
 System.out.println(s);
 
 // Find length of string
 
 n = s.length();
 System.out.println("Number of characters = " + n);
 
 // Replace characters in string
 
 t = s.replace("Java", "C++");
 System.out.println(s);
 System.out.println(t);
 
 // Concatenating string with another string
 
 u = s.concat(" is fun");
 System.out.println(s);
 System.out.println(u);
 }
}</pre>
</div>
Output 
 
<img alt="Java string methods program" src="http://www.programmingsimplified.com/images/java/string-methods-java.png" />

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Java methods

blogger 0 concept, core java, java, methods, program 07:30

Java methods tutorial: Java program consists of one or more classes and a class may contain method(s). A class can do very little without methods. In this tutorial we will learn about Java methods. Methods are… Read more »

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