You can either setLength to be 0 or create a new StringBuilder() instance. See the example below −
public class Tester { public static void main(String[] args) { StringBuilder builder = new StringBuilder(); builder.append("sample"); System.out.println(builder.toString()); builder.setLength(0); System.out.println(builder.toString()); builder.append("sample"); System.out.println(builder.toString()); } }
sample sample