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up vote 4 down vote favorite
1

I looked into Java source code and the method is like follows:

public static Object newInstance(Class<?> componentType, int length)
    throws NegativeArraySizeException {
    return newArray(componentType, length);
}

private static native Object newArray(Class componentType, int length)
    throws NegativeArraySizeException;

It seems it does not have any code in the method newArray() to build an array. Can anyone explain how it builds an array? T

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5  
It's pretty much hardcoded into Java, or in other words, it uses black magic. –  Louis Wasserman Jul 23 '13 at 17:36
    
native methods delegate to C code. –  Sotirios Delimanolis Jul 23 '13 at 17:37

2 Answers 2

up vote 5 down vote accepted

This is a native method.

That means it's implemented by native code within the JRE.

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up vote 1 down vote

It is hard-coded into the JVM (not the compiler). You could download the source code of OpenJDK or any other open-source Java Virtual Machine and look there ;)

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2  
Any idea where to look? –  SLaks Jul 23 '13 at 17:38
    
Start here: hg.openjdk.java.net/jdk8/jdk8/jdk/file/9b6070690e50/src/share/… –  Sebastian Redl Jul 23 '13 at 17:48
    
Then go here: hg.openjdk.java.net/jdk7/jdk7/hotspot/file/tip/src/share/vm/… - at this point, you should realize that this is intimately connected to the JVM internals and there's really no point in trying to understand the code. –  Sebastian Redl Jul 23 '13 at 17:57
    
hg.openjdk.java.net/jdk8/jdk8/hotspot/file/bb416ee2a79b/src/… line 319 –  Esailija Jul 23 '13 at 17:58
    
@Esailija hg.openjdk.java.net/jdk7/jdk7/hotspot/file/9b0ca45cd756/src/… –  Sebastian Redl Jul 23 '13 at 18:02

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