**`previousSetBit()`** is an instance method of the `BitSet` class that is used to get the index of the first bit that is set to `true` on or before the given beginning index. The method returns `-1` if no bit is set.

The `previousSetBit` method is defined in the `BitSet` class. The `BitSet` class is defined in the `java.util` package. To import the `BitSet` class, use the following import statement.
```
import java.util.BitSet;
```

#   
## Syntax

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``` java
public int previousSetBit(int fromIndex)
```

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## Parameters 

- `int fromIndex`: The starting index.

## Return value

This method returns the index of the previous set bit.

import java.util.BitSet;

public class Main{

    public static void main(String[] args) {
        // Create empty BitSet object
        BitSet bitSet = new BitSet();

        // Set the bit at index 2
        bitSet.set(2);

        // Set the bit at index 8
        bitSet.set(8);

        int startingIndex = 4;

        // get the first bit set to true from the startingIndex
        System.out.printf("%s.previousSetBit(%s) = %s", bitSet, startingIndex, bitSet.previousSetBit(startingIndex));
    }
}

What is BitSet.previousSetBit() in Java?

Finds the index of the first true bit before or at a specified index; returns -1 if none.

What is BitSet.previousSetBit() in Java?

Syntax

Parameters

Return value

Code