package studyjava; public class TestDemo { private int x ; private String name ; public TestDemo(){ } public String toString(){ return "age:"+this.name; } public TestDemo(int x, String name ){ this.name= name; this .x = x; } public static void main(String[] args) { TestDemo testDemo =new TestDemo(18,"LJR"); String str = "hello"; System.out.println(testDemo.toString()+str); String s1= "123"; String s2 = "123"; System.out.println(s1==s2); String s3 = s1 ; System.out.println(s1); System.out.println(s3==s1); System.out.println(s3 ==s2 ); int x =Integer.parseInt("123"); System.out.println(x); String string = " alksjdfbkb one bot"; System.out.println(string.contains("bot")); } }