I have this java class:

```
import java.util.HashMap;

public class Code39 implements LinearBarcode {
private String code;
private int[] bars;

public Code39(String code) {
    this.code = code.toUpperCase().trim();

    bars = new int[(code.length() + 2) * 12];

    this.buildSequence();
}

@Override
public void buildSequence() {
    String encoded = "*" + code + "*";

    int p = 0;
    for (int i = 0; i < encoded.length(); i++) {
        int[] sequence = mapSequence(encoded.charAt(i), i);
        System.arraycopy(sequence, 0, bars, p, sequence.length);
        p += sequence.length;
    }
}

@Override
public int[] mapSequence(char c, int pos) {
    HashMap<Character, int[]> sequence = new HashMap<Character, int[]>();

    sequence.put('0', new int[]{1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1});
    sequence.put('1', new int[]{1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1});
    sequence.put('2', new int[]{1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1});
    sequence.put('3', new int[]{1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1});
    sequence.put('4', new int[]{1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1});
    sequence.put('5', new int[]{1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1});
    sequence.put('6', new int[]{1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1});
    sequence.put('7', new int[]{1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1});
    sequence.put('8', new int[]{1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1});
    sequence.put('9', new int[]{1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1});
    sequence.put('A', new int[]{1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1});
    sequence.put('B', new int[]{1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1});
    sequence.put('C', new int[]{1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1});
    sequence.put('D', new int[]{1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1});
    sequence.put('E', new int[]{1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1});
    sequence.put('F', new int[]{1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1});
    sequence.put('G', new int[]{1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1});
    sequence.put('H', new int[]{1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1});
    sequence.put('I', new int[]{1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1});
    sequence.put('J', new int[]{1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1});
    sequence.put('K', new int[]{1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1});
    sequence.put('L', new int[]{1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1});
    sequence.put('M', new int[]{1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1});
    sequence.put('N', new int[]{1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1});
    sequence.put('O', new int[]{1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1});
    sequence.put('P', new int[]{1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1});
    sequence.put('Q', new int[]{1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1});
    sequence.put('R', new int[]{1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1});
    sequence.put('S', new int[]{1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1});
    sequence.put('T', new int[]{1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1});
    sequence.put('U', new int[]{1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1});
    sequence.put('V', new int[]{1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1});
    sequence.put('W', new int[]{1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1});
    sequence.put('X', new int[]{1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1});
    sequence.put('Y', new int[]{1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1});
    sequence.put('Z', new int[]{1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1});
    sequence.put('-', new int[]{1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1});
    sequence.put('.', new int[]{1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1});
    sequence.put(' ', new int[]{1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1});
    sequence.put('$', new int[]{1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1});
    sequence.put('/', new int[]{1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1});
    sequence.put('+', new int[]{1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1});
    sequence.put('%', new int[]{1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1});
    sequence.put('*', new int[]{1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1});

    return sequence.get(c);
}

@Override
public int[] barcode() {
    return bars;
}

@Override
public String code() {
    return code;
}

@Override
public int calculateCheckDigit() {
    return 0;
}
}

```

It generates a Code38 Linear Barcode. It returns the int[] bars array. How do I convert that array into a barcode image. I don't want to use any external jars/libs. 

If anyone has any better ideas for generating barcode images that would also be welcomed.