How Many Objects Does a Java String Create? Literal vs new String Explained

The article explains how many objects are created in Java when assigning a string literal or using the new String constructor, focusing on the roles of the string constant pool, the stack, and the heap.

1. String a = "abc" – literal assignment

When the literal "abc" is used, the JVM first checks the string constant pool. If the literal does not exist, it is created in the pool. Then a char array containing 'a','b','c' is allocated on the stack, a String object is created on the heap using that array, and finally the reference a is set to point to the pool entry.

常量池中不存在 "abc" 字符串：
（1）在栈中创建 3 个 char 型字符 'a','b','c'
（2）在堆中 new 一个 String 对象，内部保存上述 char 数组
（3）把该 String 对象放入字符串常量池
（4）a 指向常量池中该对象的地址

2. Equivalent representation

The same effect can be expressed explicitly with a character array:

char data[] = {'a','b','c'};
String a = new String(data);

3. String a = new String("abc") – explicit constructor

This form always creates a new heap object regardless of whether the literal already exists in the constant pool. The steps are:

Define a reference variable a on the stack.

Allocate a new String object on the heap and assign it to a.

The newly created String object internally references the literal "abc" in the constant pool.

4. Reference comparison example

String a = "abc";
String b = "abc";
String c = new String("abc");
String d = new String("abc");
System.out.println(a == b); // true
System.out.println(a == c); // false
System.out.println(c == d); // false

The output true, false, false shows that literals share the same pool object, while each new String call creates a distinct heap object, so their references are not equal.

5. Conclusion

Using a string literal may create zero or one object (if the literal is already in the pool). Using new String always creates at least one new heap object, and the literal may also reside in the pool, resulting in two objects in total. Therefore, reference equality behaves as demonstrated above.