Java Strings — Free Java Tutorial

TL;DR: Learn Java Strings in Java with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Java Strings in Java

Strings in Java are objects of the String class — immutable (cannot be changed). Every time you modify a String, a new object is created in memory.

For frequent modifications, use StringBuilder (not thread-safe, faster) or StringBuffer (thread-safe). Both are mutable.

Important String methods: length(), charAt(i), substring(start,end), indexOf(s), contains(s), startsWith(s), toUpperCase(), toLowerCase(), trim(), replace(old,new), split(regex), equals(), equalsIgnoreCase().

String.format() and printf() use format specifiers: %s (string), %d (integer), %f (float), %n (newline). Java 15+ adds text blocks with triple quotes."""

String s = "Hello World";
s.length()           // 11
s.charAt(0)          // 'H'
s.substring(6, 11)   // "World"
s.toUpperCase()      // "HELLO WORLD"
s.contains("World")  // true
s.replace("World","Java")  // "Hello Java"
s.split(" ")         // ["Hello","World"]
s.trim()             // removes lea

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