This two codes have defferent outputs and i don't know why.
String a="abc"; String b="abc"; System.out.println(a==b + " " + a.equals(b)); The output is "true true"
String a="abc"; String b=new String("abc"); System.out.println(a==b + " " + a.equals(b)); The output is "false true"
when you use this
String a="abc"; String b="abc"; the java creates only one object in memory which is abc and here a and b are pointing to same object and == don't check the string content instead it check the reference value. but as soon as you do this
String b=new String("abc"); java creates a new object b in memory which is different from a ,now b and a are pointing to two different objects hence if you compare contents with equals function result will be true but if you compare reference now, result will be false
b because ` b="qwe";` means ` b=new String("qwe");`. String objects has this shortcut feature.This has to be a duplicate of a large number of questions, but I will comment by saying that when you do the following:
String a = "abc"; String b = "abc"; The JVM creates a single String object in the constant pool which contains the String abc. Hence, the a and b Strings simply point to the same string in the pool.
However, when you do the following:
String a = "abc"; String b = new String("abc"); a new object is created even though abc already exists in the pool. Hence the comparison a == b returns false, although the contents of both these strings remains equivalent.
== compares the memory location, and equals() compares the content of the Strings.