BitSet is a class in java.util that represents a vector of bits that grows as needed. It is a memory-efficient alternative to using arrays of booleans or integers to track flags or binary states.
Scenarios
- Efficiently represent sets of flags or toggles.
- Perform fast bitwise operations (AND, OR, XOR, etc.).
- Solve problems involving combinations, masks, or presence/absence indicators.
- Common in low-level data structures, bloom filters, or scheduling applications.
Sample Usage
import java.util.BitSet;
public class BitSetExample {
public static void main(String[] args) {
BitSet flags = new BitSet();
// Set some bits
flags.set(0); // true at index 0
flags.set(3); // true at index 3
// Check a bit
System.out.println(flags.get(0)); // true
System.out.println(flags.get(1)); // false
// Flip a bit
flags.flip(1);
System.out.println(flags.get(1)); // true
// Clear a bit
flags.clear(3);
// Print all set bits
System.out.println(flags); // {0, 1}
}
}
BitSet is useful when dealing with large datasets where space and performance are critical.