There are 4 internal indicators (capacity, limit, position, remaining) in Buffer classes, example below shows the change of these indicators.

import java.nio.Buffer;
import java.nio.ByteBuffer;

public class BufferTest {

	public static void main(String[] args) {
		ByteBuffer buf = ByteBuffer.allocate(8);
		System.out.println("[new buf]");
		printBufferInfo(buf);

		buf.put((byte) 1).put((byte) 2).put((byte) 3);
		System.out.println("[put 3 elements]");
		printBufferInfo(buf);

		for (int i = 0; i < buf.position(); i++)
			System.out.println(buf.get(i));
		System.out.println("[get 3 elements by index]");
		printBufferInfo(buf);

		buf.flip();
		System.out.println("[flip]");
		printBufferInfo(buf);

		for (int i = 0; i < 2; i++)
			System.out.println(buf.get());
		System.out.println("[get 2 elements]");
		printBufferInfo(buf);

		buf.compact();
		System.out.println("[compat]");
		printBufferInfo(buf);

		buf.put((byte) 4);
		System.out.println("[put 1 element]");
		printBufferInfo(buf);

		buf.clear();
		System.out.println("[clear]");
		printBufferInfo(buf);
	}

	public static void printBufferInfo(Buffer buf) {
		System.out.println("Capacity: " + buf.capacity());
		System.out.println("Limit: " + buf.limit());
		System.out.println("Position: " + buf.position());
		System.out.println("Remaining: " + buf.remaining());
	}

}

The output is

[new buf]
Capacity: 8
Limit: 8
Position: 0
Remaining: 8
[put 3 elements]
Capacity: 8
Limit: 8
Position: 3
Remaining: 5
1
2
3
[get 3 elements by index]
Capacity: 8
Limit: 8
Position: 3
Remaining: 5
[flip]
Capacity: 8
Limit: 3
Position: 0
Remaining: 3
1
2
[get 2 elements]
Capacity: 8
Limit: 3
Position: 2
Remaining: 1
[compat]
Capacity: 8
Limit: 8
Position: 1
Remaining: 7
[put 1 element]
Capacity: 8
Limit: 8
Position: 2
Remaining: 6
[clear]
Capacity: 8
Limit: 8
Position: 0
Remaining: 8