Java native method source code

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Where to find source code for java.lang native methods? [closed] 2 answers

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You can download OpenJdk source code here.

In the folder jdksrcshare you can get source code.

jdksrcsharenative is the natice method souce write in c and c++.

jdksrclinux source for linux.

jdksrcwindows source for windows.

jdksrcsolaris souce for solaris.

jdsrcshare common source.

eg: System.arrayCopy();

int file hotspotsrcsharevmoopsobjArrayKlass.cpp line 168:

void objArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
                           int dst_pos, int length, TRAPS) {
assert(s->is_objArray(), "must be obj array");

if (!d->is_objArray()) {
  THROW(vmSymbols::java_lang_ArrayStoreException());
}

// Check is all offsets and lengths are non negative
if (src_pos < 0 || dst_pos < 0 || length < 0) {
  THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
}
// Check if the ranges are valid
if  ( (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length())
   || (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length()) )   {
  THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
}

// Special case. Boundary cases must be checked first
// This allows the following call: copy_array(s, s.length(), d.length(), 0).
// This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
// points to the right of the last element.
if (length==0) {
  return;
}
if (UseCompressedOops) {
  narrowOop* const src = objArrayOop(s)->obj_at_addr<narrowOop>(src_pos);
  narrowOop* const dst = objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos);
  do_copy<narrowOop>(s, src, d, dst, length, CHECK);
} else {
  oop* const src = objArrayOop(s)->obj_at_addr<oop>(src_pos);
  oop* const dst = objArrayOop(d)->obj_at_addr<oop>(dst_pos);
  do_copy<oop> (s, src, d, dst, length, CHECK);
  }
}

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Native methods and implemented differently by the Virtual Machine you are using. There is no one implementation of this method, and in fact different code may be executed on different architectures or VMs.

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