javalangString

javalangString is not an official Java API term, but is sometimes used informally to refer to the string data type in Java, as implemented by the class java.lang.String. In this sense, javalangString denotes the immutable sequence of Unicode code units used to represent text in Java applications.

Java strings are instances of the final class java.lang.String. They are immutable, meaning that once created, the character data they hold cannot be changed. A javalangString value is typically created from string literals, the new String constructor, or factory methods such as String.valueOf. The internal representation uses UTF-16 code units, and common operations rely on methods provided by String, such as length(), charAt(int), substring(int,int), equals(Object), and hashCode().

Key methods and behavior include:

- length(), charAt(int), substring(int, int)

- equals(Object), compareTo(String), equalsIgnoreCase(String)

- startsWith(String), endsWith(String), contains(CharSequence)

- indexOf(String), lastIndexOf(String), trim(), replace(CharSequence, CharSequence)

- toLowerCase(), toUpperCase(), split(String)

- valueOf(Object), copyValueOf(char[]), intern()

Interning plays a role in memory efficiency: string literals are typically pooled, and intern() can be used to canonicalize strings at runtime.

Common considerations: Java favors immutability for safety and thread-safety. Repeated string concatenation in loops is inefficient; prefer StringBuilder or StringBuffer for such operations. Locale-sensitive case conversions and normalization can affect results, so locale-aware methods may be necessary for internationalized applications.