Answer Happy

Could you please help me convert the following code to maxHeap instead,
import java.util.*;
import java.io.*;
class Main {

private String[] Heap;
private int size;
private int maxsize;
private static final int FRONT = 1;
public Main(int maxsize)
{
this.maxsize = maxsize;
this.size = 0;

Heap = new String[this.maxsize + 1];
Heap[0] ="";
}
private int parent(int pos) { return pos / 2; }
private int leftChild(int pos) { return (2 * pos); }
private int rightChild(int pos)
{
return (2 * pos) + 1;
}
private boolean isLeaf(int pos)
{

if (pos > (size / 2) && pos <= size) {
return true;
}

return false;
}
private void swap(int fpos, int spos)
{

String tmp;
tmp = Heap[fpos];

Heap[fpos] = Heap[spos];
Heap[spos] = tmp;
}
private void minHeapify(int pos)
{
if (!isLeaf(pos)) {
if (Heap[pos].compareTo(Heap[leftChild(pos)]) > 0
|| Heap[pos].compareTo(Heap[rightChild(pos)]) > 0)
{
if (Heap[leftChild(pos)].compareTo(Heap[rightChild(pos)]) < 0) {
swap(pos, leftChild(pos));
minHeapify(leftChild(pos));
}
else {
swap(pos, rightChild(pos));
minHeapify(rightChild(pos));
}
}
}
}
public void insert(String element)
{

if (size >= maxsize) {
return;
}

Heap[++size] = element;
int current = size;

while (Heap[current].compareTo(Heap[parent(current)]) < 0) {
swap(current, parent(current));
current = parent(current);
}
}
public void printHeap()
{
for (int i = 1; i <= size; ++i)
System.out.print(Heap + " ");

System.out.println();
}
public String giveTop()
{
return Heap[FRONT];
}
public String remove()
{

String popped = Heap[FRONT];
Heap[FRONT] = Heap[size--];
minHeapify(FRONT);

return popped;
}

public static void main(String[] args) throws FileNotFoundException
{
System.out.println("Step by step formation of min heap:");
Main minHeap = new Main(100);
Scanner readMyFile = new Scanner(new File("heapin.txt"));
String data = readMyFile.nextLine();
String[] nodes = data.split(", ");
for (String s: nodes) {
minHeap.insert(s);
minHeap.printHeap();
}

System.out.println("Heap sort implementation:");
for(int i = 0; i < nodes.length - 1 ; i++)
{
System.out.print(minHeap.remove() +" ");
}
System.out.println(minHeap.giveTop());

}
}
The heapin.txt:
RR, BB, YY, GG, NN, QQ, MM, PP, BB, AA, KT, UV, VV, GG, QQ, MN, PQ, RS, TU, YM