GNU Compiler for Java


GNU Compiler for Java
GNU Compiler for Java
Gcj2.png
Developer(s) The GNU Project
Stable release 4.6.1 / June 27, 2011; 4 months ago (2011-06-27)
Operating system Unix-like
Type Compiler
License GNU GPL
Website http://gcc.gnu.org/java

The GNU Compiler for Java (GCJ or gcj) is a free software compiler for the Java programming language and a part of the GNU Compiler Collection.

GCJ can compile Java source code to either Java Virtual Machine bytecode, or directly to machine code for any of a number of CPU architectures. It can also compile class files containing bytecode or entire JARs containing such files into machine code.

Contents

History

Almost all of the runtime-libraries used by gcj come from the GNU Classpath project (but compare the libgcj library). As of gcj 4.3, gcj integrates with ecj, the Eclipse Compiler for Java.[1]

As of 2007 a lot of work has gone in to getting GNU Classpath to support Java's two graphical APIs: AWT and Swing. Work on supporting AWT is ongoing, after which support for Swing will follow.[2]

As of 2009 there have been no new developments announced from gcj.[3] The product is currently in maintenance mode.

Performance

Java code compiled into machine code by GCJ should have faster start-up time than the equivalent bytecode launched in a JVM.[4]

However, after start-up, Java code compiled by GCJ does not necessarily execute any faster than bytecode executed by a modern JIT-enabled JVM. This is true even when GCJ is invoked with advanced optimization options such as -fno-bounds-check -O3 -mfpmath=sse -msse2 -ffast-math -march=native; in this case, the compiled program may or may not surpass JVM performance, depending on the operations performed by the code in question.[5]

CNI (Compiled Native Interface)

The CNI (Compiled Native Interface, previously Cygnus Native Interface), a software framework for the gcj, allows Java code to call and be called by native applications (programs specific to a hardware and operating-system platform) and libraries written in C++.

CNI closely resembles the Java Native Interface (JNI) framework which comes as standard with various Java virtual machines. However the CNI authors claim various advantages over JNI:[6]

We use CNI because we think it is a better solution, especially for a Java implementation that is based on the idea that Java is just another programming language that can be implemented using standard compilation techniques. Given that, and the idea that languages implemented using Gcc should be compatible where it makes sense, it follows that the Java calling convention should be as similar as practical to that used for other languages, especially C++, since we can think of Java as a subset of C++. CNI is just a set of helper functions and conventions built on the idea that C++ and Java have the *same* calling convention and object layout; they are binary compatible. (This is a simplification, but close enough.)

CNI depends on Java classes appearing as C++ classes. For example,[7] given a Java class,

public class Int
{
   public int i;
   public Int(int i) { this.i = i; }
   public static Int zero = new Int(0);
}

one can use the class thus:

#include <gcj/cni.h>
#include <Int>
 
Int *mult(Int *p, int k)
{
  if (k == 0)
    return Int::zero;  // Static member access.
  return new Int(p->i * k);
}

See also

References

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • GNU Compiler for Java — Тип Компилятор Разработчик Проект GNU Операционная …   Википедия

  • GNU Compiler for Java — Entwickler The GNU Project Aktuelle Version 4.4.2 (15. Oktober 2009) Betriebssystem …   Deutsch Wikipedia

  • GNU Compiler for Java — GCJ ejecutado en una consola dentro de gnome terminal …   Wikipedia Español

  • GNU Interpreter for Java — The GNU Interpreter for Java (GIJ) is a Java bytecode interpreter for the Java programming language.It is part of the free software GNU Compiler for Java (GCJ). GCJ is the compiler counterpart to GIJ. See also *Free Java implementations External… …   Wikipedia

  • GNU Compiler for the Java Programming Language — GNU Compiler for Java Entwickler: The GNU Project Aktuelle Version: 4.3.1 (6. Juni 2008) Betriebssystem …   Deutsch Wikipedia

  • GNU Compiler Collection — Entwickler GCC Team Aktuelle Version 4.6.2 (26. Oktober 2011) Betriebssyste …   Deutsch Wikipedia

  • GNU Compiler Collection — Cc1 redirects here. For other uses of CC1 or CC 1, see CC1 (disambiguation). GNU Compiler Collection Developer(s) GNU Project Initial release May 23, 1987 ( …   Wikipedia

  • GNU Compiler Collection — GNU Compiler Collection …   Википедия

  • GNU Compiler Collection — GCC invocado desde la línea de comandos en Debian …   Wikipedia Español

  • Java (Framework) — Java Objektorientierte Programmiersprache Basisdaten Paradigmen: Objektorientierte Programmiersprache Aktuelle  …   Deutsch Wikipedia