Difference between string object and string literal [duplicate]

Answer 1

As Strings are immutable, when you do:

String a = "xyz"

while creating the string, the JVM searches in the pool of strings if there already exists a string value "xyz", if so 'a' will simply be a reference of that string and no new String object is created.

But if you say:

String a = new String("xyz")

you force JVM to create a new String reference, even if "xyz" is in its pool.

For more information read this.

Answer 2

"abc" is a literal String.

In Java, these literal strings are pooled internally and the same String instance of "abc" is used where ever you have that string literal declared in your code. So "abc" == "abc" will always be true as they are both the same String instance.

Using the String.intern() method you can add any string you like to the internally pooled strings, these will be kept in memory until java exits.

On the other hand, using new String("abc") will create a new string object in memory, which is logically the same as the "abc" literal. "abc" == new String("abc") will always be false, as although they are logically equal they refer to different instances.

Wrapping a String constructor around a string literal is of no value, it just needlessly uses more memory than it needs to.

Answer 3

According to String class documentation they are equivalent.

Documentation for String(String original) also says that: Unless an explicit copy of original is needed, use of this constructor is unnecessary since Strings are immutable.

Look for other responses, because it seems that Java documentation is misleading :(

Answer 4

In the first case, there are two objects created.

In the second case, it's just one.

Although both ways str is referring to "abc".

Answer 5

A String literal is a Java language concept. This is a String literal:

"a String literal"

A String object is an individual instance of the java.lang.String class.

String s1 = "abcde";
String s2 = new String("abcde");
String s3 = "abcde";

All are valid, but have a slight difference. s1 will refer to an interned String object. This means, that the character sequence "abcde" will be stored at a central place, and whenever the same literal "abcde" is used again, the JVM will not create a new String object but use the reference of the cached String.

s2 is guranteed to be a new String object, so in this case we have:

s1 == s2 // is false
s1 == s3 // is true
s1.equals(s2) // is true

Answer 6

There is a subtle differences between String object and string literal.

String s = "abc"; // creates one String object and one reference variable

In this simple case, "abc" will go in the pool and s will refer to it.

String s = new String("abc"); // creates two objects,and one reference variable

In this case, because we used the new keyword, Java will create a new String object in normal (non-pool) memory, and s will refer to it. In addition, the literal "abc" will be placed in the pool.