4-5.txt

清华大学第二版

public class StringTest {
	public static void main(String args[]) {
		String s = "This is a test String!";
		System.out.println("before changed, s= " + s);
	
		String t = s.toLowerCase();
		System.out.println("after changed, s= " + s);
		System.out.println("t= " + t);
	}
}