Where to find source code for java.lang native methods?

java java-native-interface native
Ben Simmons picture Ben Simmons · Feb 18, 2010 · Viewed 25.9k times · Source

I'm vaguely familiar with the JNI, and I'm curious to see my machine-specific implementation for some native methods in the java.lang package. Thread#currentThread(), for example.

I've found a bunch of DLLs in [JDK_HOME]/jre/bin, but like I said I'm trying to find the source code.

Does anyone know where the native source code can be found? Is it even available, or is it classified by Sun (oops I mean "We're In It To Win It" Oracle)?

Answer

Tom Hawtin - tackline picture Tom Hawtin - tackline · Feb 18, 2010

For JDK6 you can download the source from java.net. For java.lang the story begins at j2se/src/share/native/java/lang/, and then search... JDK7 rearranges the directory structure a little.

Some methods, such as Object.hashCode, may be implemented by hotspot instead or in addition to through JNI/Java.

JDK6 is freely licensed through the Java Research License (JRL) and Java Internal Use License (JIUL). JDK7 and OpenJDK6 is licensed under GPL 2 with CLASSPATH exception (roughly speaking you can link to it without catching the GNU virus). I am not a lawyer.

(BTW: The real lawyers would like to point out that I am still an employee of Sun Microsystems. Sun UK is no more. It is now Oracle.)

Update (Adding location for Thread.c): http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/9b8c96f96a0f/src/share/native/java/lang/Thread.c

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