Java String Methods

Strings in Java are objects that represent sequences of characters. The String class provides powerful methods to manipulate text easily

1 length() – Find string length

String str = "Java";
System.out.println(str.length()); // 4

2 charAt() – Get character at index

System.out.println(str.charAt(1)); // a

3 toUpperCase() and toLowerCase()

System.out.println(str.toUpperCase()); // JAVA
System.out.println(str.toLowerCase()); // java

4 trim() – Remove extra spaces

String text = " Hello ";
System.out.println(text.trim()); // Hello

5 equals() – Compare strings

String a = "Java";
String b = "Java";
System.out.println(a.equals(b)); // true

6 equalsIgnoreCase() – Ignore case

System.out.println("java".equalsIgnoreCase("JAVA")); // true

7 contains() – Check substring

System.out.println("Hello Java".contains("Java")); // true

8 startsWith() and endsWith()

String s = "Java Programming";
System.out.println(s.startsWith("Java")); // true
System.out.println(s.endsWith("ing")); // true

9 indexOf() – Find position

System.out.println("Java".indexOf('a')); // 1

10 lastIndexOf()

System.out.println("banana".lastIndexOf('a')); // 5

11 substring() – Extract part

String s = "Hello World";
System.out.println(s.substring(0, 5)); // Hello