Why Can You Create Strings in Java Without the 'new' Keyword?

Strings: Objects without the "new" Keyword

Java strings are indeed objects, yet they are unique in that they can be created without the "new" keyword. This raises the question: why?

Initially, strings may appear to be created like other objects:

Object obj = new Object();

However, strings are not initialized in this manner:

String str = "Hello World";

Interning of String Literals

To understand this discrepancy, we need to delve into the concept of string interning. Interning means that every occurrence of a specific string literal (e.g., "abcd") refers to a single instance of that string, rather than creating a new instance each time.

In Java, strings declared with double quotes are treated as literals and are automatically interned. This means that:

String a = "abcd";
String b = "abcd";

will result in:

a == b; // True

String Creation with "new"

Although interning is enabled for string literals, you can still create strings using the "new" keyword:

String a = new String("abcd");
String b = new String("abcd");

However, in this case, it is possible to have:

a == b; // False

Benefits of Interning

Interning string literals provides several benefits:

• Performance: By using a single instance for each unique string, the JVM allocates less memory and performs fewer object creations.
• Memory Savings: Interning ensures that only a single instance exists for each distinct string, reducing the memory footprint.
• Equality Checking: Using "==" for string literals is valid because it checks for physical equality, which is guaranteed due to interning.

Note: It's always recommended to use the .equals() method for comparing strings, even for interned strings, since it checks for content equality.

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