What do << or >>> in java mean?

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What does >> and >>> mean in Java?

I ran across some unfamiliar symbols in some java code, and while the code compiles and functions correctly, I am confused as to what exactly the angle brackets are doing in this code. I found the code in com.sun.java.help.search.BitBuffer, a fragment of which is below:

public void append(int source, int kBits)
    {
        if (kBits < _avail)
        {
            _word = (_word << kBits) | source;
            _avail -= kBits;
        }
        else if (kBits > _avail)
        {
            int leftover = kBits - _avail;
            store((_word << _avail) | (source >>> leftover));
            _word = source;
            _avail = NBits - leftover;
        }
        else
        {
            store((_word << kBits) | source);
            _word = 0;
            _avail = NBits;
        }
    }

What do those mysterious looking brackets do? It almost looks like c++ insertion/extraction, but I know that Java doesn't have anything like that.

Also, I tried googling it, but for some reason Google seems to not see the angle brackets, even if I put them in quotes.

They are Bit-Shift operators, read about it [here](http://docs.oracle.com/javase/tutorial/java/nutsandbolts/operators.html) and more detailed [here](http://docs.oracle.com/javase/tutorial/java/nutsandbolts/op3.html) — jlordo, Nov 14 '12 at 21:10
Just to add, >>> right shifting of bits means dividing the number by no of bit shifts raised to the power of 2 and << left shifting of bits means multiplying the number by no of bit shifts raised to the power of 2 — Aarish Ramesh, Sep 20 '17 at 08:19

score 47 · Accepted Answer · edited Jun 20 '20 at 09:12

47

They are Bitwise Bit shift operators, they operate by shifting the number of bits being specified . Here is tutorial on how to use them.

The signed left shift operator "<<" shifts a bit pattern to the left

The signed right shift operator ">>" shifts a bit pattern to the right.

The unsigned right shift operator ">>>" shifts a zero into the leftmost position

edited Jun 20 '20 at 09:12

Community

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answered Nov 14 '12 at 21:10

kosa

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The code is also using `>>>` which is an unsigned right shift. – TheZ Nov 14 '12 at 21:14
@TheZ: Thanks! Updated answer with related text. – kosa Nov 14 '12 at 21:18

score 8 · Answer 2 · answered Nov 14 '12 at 21:10

straight from ORACLE DOC.

The signed left shift operator "<<" shifts a bit pattern to the left, and the signed right shift operator ">>" shifts a bit pattern to the right. The bit pattern is given by the left-hand operand, and the number of positions to shift by the right-hand operand. The unsigned right shift operator ">>>" shifts a zero into the leftmost position, while the leftmost position after ">>" depends on sign extension.

score 4 · Answer 3 · answered Nov 14 '12 at 21:11

4

Bitwise shifting. Please see the official docs here: http://docs.oracle.com/javase/tutorial/java/nutsandbolts/op3.html

answered Nov 14 '12 at 21:11

Kristof Jozsa

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What do << or >>> in java mean?

3 Answers3