javalangInteger

javalangInteger is not the official name of a Java class. In the Java API, the wrapper for the primitive int is java.lang.Integer. This article describes that class and its common uses, noting that a term like javalangInteger often refers to java.lang.Integer by shorthand or misspelling.

Integer is a final class that extends Number and implements Comparable<Integer>. It encapsulates a 32-bit signed value as an object, enabling integers to be used in contexts that require objects, such as collections or generics. Instances are immutable. Java supports autoboxing and unboxing between int and Integer, so code can often treat them interchangeably. Since Java 9, the public constructors (for example, new Integer(int)) are deprecated in favor of factory methods like Integer.valueOf(int).

Constructors and factory methods include public Integer(int value) (deprecated), public Integer(String s) (may throw NumberFormatException), and static factory methods such as Integer.valueOf(int i) and Integer.valueOf(String s, int radix). The class also provides parse and decode utilities for converting strings to integers, and methods for unsigned arithmetic and parsing, such as parseInt, parseUnsignedInt, decode, and toUnsignedString.

Key constants are MAX_VALUE, MIN_VALUE, SIZE (32 bits), and BYTES (4). Important instance and static methods include intValue, longValue, floatValue, doubleValue, compareTo, equals, hashCode, and toString. Static utility methods cover parsing, digit conversion, and bit-level operations like highestOneBit and numberOfLeadingZeros.

Usage notes: Java programs frequently rely on Integer for object wrappers in collections and APIs that require objects. Autoboxing simplifies usage, but boxing/unboxing can affect performance in tight loops. Cache behavior typically covers values from -128 to 127 via valueOf.