Java - Regular Expressions Part 1: Understanding the Basics of Regex in Java

Key Classes in java.util.regex:

Pattern: Compiles a regex into a reusable pattern.

Matcher: Matches the compiled pattern against the text.

PatternSyntaxException: Catches invalid regex syntax.

Example 1: Simple Match

String pattern = "hello";

String text = "hello world";

boolean matches = text.matches(".*" + pattern + ".*"); // true

System.out.println("Match found: " + matches);

Example 2: Case Sensitivity

String pattern = "Hello";

String text = "hello world";

boolean matches = text.matches(".*" + pattern + ".*"); // false

System.out.println("Case-sensitive match: " + matches);

Example 3: Compiling a Pattern

Pattern pattern = Pattern.compile("java");

Matcher matcher = pattern.matcher("I love java programming");

System.out.println("Match found: " + matcher.find()); // true