Outline of the Java programming language

The following outline is provided as an overview of and topical guide to Java:

Java is a general-purpose, concurrent, object-oriented, class-based, strong, and statically typed programming language that is compiled to JVM bytecode for execution on a Java virtual machine (JVM), which allows "write once, run anywhere" programming. Java was designed by James Gosling and a team at Sun Microsystems in the early 1990s and was a core component of Sun's Java platform.

Type of language

Programming language – artificial language designed to communicate instructions to a machine, more so a computer.
Object-oriented programming – built mostly around objects and classes.
Class-based programming – types and code are organized into classes.
Compiled – source code is compiled to an intermediate representation: JVM bytecode.
Interpreted – bytecode is executed by a Java virtual machine, which typically performs Just-in-time compilation.
General-purpose programming language – designed for a wide variety of application domains.
Static type checking – type checking is performed at compile time.
Strongly typed – enforces strict type rules at compile time.
Concurrent – built-in support for multithreading and concurrency utilities.

Oak – early name for a new programming language started at Sun Microsystems
Acquisition of Sun Microsystems by Oracle Corporation in 2010, along with the Java programming language and APIs.
Oracle litigation against Google's Android OS for using Java APIs from Oracle. See also: Comparison of Java and Android API
Java 25 – latest major release published September 16, 2025

Abstraction from hardware – students miss low-level cost models
Array limits – capped size and no true multidimensional arrays
Checked exceptions – criticized as verbose and largely abandoned by other languages
Floating-point limits – incomplete IEEE 754 support
Generics via type erasure – limits expressiveness and caused unsoundness bugs
Java performance – early implementations were slow compared to C/C++
Primitive vs. object divide – forces code duplication in libraries
Serialization – widely seen as a serious security risk
Lack of tuples – requires awkward workarounds or third-party libraries
Licensing and governance controversies – Sun Microsystems acquisition by Oracle and subsequent litigation
No operator overloading – makes math-heavy code less readable
Potential sources of security vulnerabilities in Java applications
Project Valhalla (missing value types) – inefficiency due to everything being objects
Security vulnerabilities – repeated sandbox escapes and exploit waves
Unsigned integer types – problematic for cryptography and C interop
Weak parallelism – monitors criticized as insecure and unreliable

Java SE – Java Platform Standard Edition
Jakarta EE (formerly Java EE) – Enterprise Edition APIs and runtime for multi-tiered server applications
JavaFX
Java ME – Micro Edition for constrained devices and embedded systems

Bruce Eckel – Thinking in Java
James Gosling – The Java Programming Language
Joshua Bloch – Effective Java
Kathy Sierra – Head First Java
Herbert Schildt – Java: The Complete Reference, Java: A Beginner's Guide, Java 2 Programmer's Reference