Core Java: String literals are interned, so == matches constants but not new String

Compile-time string literals share one pooled instance so == is true between them, but new String(...) always creates a distinct object; calling intern() returns the pooled reference, making == true again.

Code

String a = "hello";
String b = "hello";
String c = new String("hello");
String d = c.intern();
System.out.println("a == b: " + (a == b));
System.out.println("a == c: " + (a == c));
System.out.println("a == d: " + (a == d));

Output

a == b: true
a == c: false
a == d: true