Can I pass a primitive type by reference in Java?

Question

I would like to call a method which could potentially take on different versions, i.e. the same method for input parameters that are of type:

• boolean
• byte

Answer 1

I would say the alternative strategy, if you want to work with primitives, is to do what the Java Libraries do. Just suck it up and have multiple methods.

For example, ObjectInputStream has readDouble(), readByte(), etc.

You're not gaining anything by sharing an implementation of the function, and the clients of your function aren't gaining anything by the variants of your function all having the same name.

UPDATE

Considering your update, I don't think it's necessary to duplicate too much code. It depends on your encoding strategy but I would imagine you could do something like this:

private byte get8Bits();
public byte getByte() {
    return get8Bits();
}
public int getInt() {
    return (get8Bits() << 24) | (get8Bits() << 16) | (get8Bits() << 8) | get8Bits();
}

Anything that shares code more than that is probably over-engineering.

An alternative could be

private long getBits(int numBits);

public byte getByte() {
    return (byte)getBits(8);
}

public int getInt() {
    return (int)getBits(32);
}

i.e. I don't think it makes sense to expose the users of your library to anything other than the primitive types themselves.

If you really, really wanted to then you could make a single method for access like this:

@SuppressWarnings("unchecked")
public static  T getValue(Class clazz) {
    if ( clazz == byte.class ) {
        return (T)Byte.valueOf((byte)getBits(8));
    } else if ( clazz == int.class ) {
        return (T)Integer.valueOf((int)getBits(32));
    }
    throw new UnsupportedOperationException(clazz.toString());
}

//...
byte b = getValue(byte.class);
int i = getValue(int.class);

But I fail to see how it's any less cumbersome for clients of your library.