String s1="a";String s2="ab";String s3="abc";------>1:s1+s2==s3?,--->2: (s1+s2).equals.s3?,--->3:System.out.print(("a"+"bc")=="abc")结果?

String s1="a";String s2="ab";String s3="abc";------>1:s1+s2==s3?,--->2: (s1+s2).equals.s3?,--->3:System.out.print(("a"+"bc")=="abc")结果?