Java String Construction and Immutability

Constructing a String in Java

• In Java, a string is constructed using double quotes, for example: String s = "Java";

String Immutability

• A String object is immutable, meaning its value cannot be changed after it is created
• When a new value is assigned to a String variable, a new String object is created, and the original object remains unchanged

String Literals and JVM

• The Java Virtual Machine (JVM) uses a unique instance for string literals with the same character sequence to conserve memory
• This means that if multiple strings have the same character sequence, they will reference the same object in memory

Interned Strings

• Interned strings are strings that are stored in a pool, allowing for efficient reuse of identical strings
• The purpose of interned strings is to reduce memory usage by avoiding the creation of duplicate strings

String Creation and Interning

• When executing the code String s1 = "Welcome to Java";, a new string object is created and interned in the string pool
• If a string with the same character sequence already exists in the pool, the existing object is reused

Comparing Strings

• Comparing two strings with the compareTo method returns 0 if they are equal
• The compareTo method compares the lexicographical order of the strings

String Methods

• The regionMatches method checks if a region of one string matches a region of another string
• The startsWith method checks if a string starts with a specified prefix