Thread: dynamically resizing 2d array

i am in need of an efficient way to resize a 2d array. the 2d array must be able to increase and decrease in size very frequently.

currently i am doing it the least efficient way possible.

public void ArrayResize(int rows , int columns){
	    	holdArray=new int[iMapTiles.length][iMapTiles[0].length];//copy the current array into temporary array
	    	for (int r=0; r < holdArray.length; r++){
	    		for (int c=0; c < holdArray[0].length; c++) 
					holdArray[r][c]=iMapTiles[r][c];
			} 	
 
 
	    	iMapTiles= new int[rows][cols];// reinstantiate the array to be the wished size
 
	        if(rows>holdArray.length||columns>holdArray[0].length){//copy the temporary array into the new array
		    	for (int j=0; j < holdArray.length; j++)
		    		for (int k=0; k < holdArray[0].length; k++) 
		    			iMapTiles[j][k]=holdArray[j][k];
	    	}else{
	    		for (int j=0; j <rows; j++)
		    		for (int k=0; k <columns; k++) 
		    			iMapTiles[j][k]=holdArray[j][k];
	    	}
 
    }

this works, but it is very slow since i re-instantiate the arrays very often. i was thinking of either implementing a 2d arraylist(seems hard) or just using variables to hold the size of the array and instantiate the array to be bigger than it actually is, then i would only have to resize it every once in a while(like an arraylist).

any tips? thanks

You can take a look at this.