Check out example codes for "java string methods". It will help you in understanding the concepts better.

Code Example 1

public char charAt(int index)
-----------------------------
String x = "airplane";
System.out.println( x.charAt(2) ); // output is 'r'

Code Example 2

static String valueOf(int i) - returns the string representation of the int 
argument.

Code Example 3

// all String methods
public class StringMethodsDemo {
	public static void main(String[] args) {
		String targetString = "Java is fun to learn";
		String s1= "JAVA";
		String s2= "Java";
		String s3 = "  Hello Java  ";
		
		System.out.println("Char at index 2(third position): " + targetString.charAt(2));
		System.out.println("After Concat: "+ targetString.concat("-Enjoy-"));
		System.out.println("Checking equals ignoring case: " +s2.equalsIgnoreCase(s1));
		System.out.println("Checking equals with case: " +s2.equals(s1));
		System.out.println("Checking Length: "+ targetString.length());
		System.out.println("Replace function: "+ targetString.replace("fun", "easy"));
		System.out.println("SubString of targetString: "+ targetString.substring(8));
		System.out.println("SubString of targetString: "+ targetString.substring(8, 12));
		System.out.println("Converting to lower case: "+ targetString.toLowerCase());
		System.out.println("Converting to upper case: "+ targetString.toUpperCase());
		System.out.println("Triming string: " + s3.trim());
		System.out.println("searching s1 in targetString: " + targetString.contains(s1));
		System.out.println("searching s2 in targetString: " + targetString.contains(s2));

		char [] charArray = s2.toCharArray();
		System.out.println("Size of char array: " + charArray.length);
		System.out.println("Printing last element of array: " + charArray[3]);

	}

}

Code Example 4

public int length()
-----------------------
String x = "01234567";
System.out.println( x.length() ); // returns "8"

Code Example 5

public String trim()

String x = " hi ";
System.out.println( x + "x" ); // result is" hi x"
System.out.println(x.trim() + "x"); // result is "hix"

Code Example 6

//string syntax.
String hello = "Hello, world!";

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