I'm current working on an RFID program. Whenever a key is pressed the following error occurs
Exception in thread "Animation Thread" java.lang.NullPointerException

at optimized.keyPressed(optimized.java:222)

at processing.core.PApplet.handleKeyEvent(PApplet.java:1724)

at processing.core.PApplet.dequeueKeyEvents(PApplet.java:1707)

at processing.core.PApplet.handleDraw(PApplet.java:1412)

at processing.core.PApplet.run(PApplet.java:1305)

at java.lang.Thread.run(Thread.java:595)

Code:

char currentTags[][];

void keyPressed() 
{ 
	print(" "+ key);
	if (key == '\n')
	{
	  //move to next tag
	  g++;
	  if(g>6){
	    g=0;
	  }
	}
	else 
	{
	  //get the character input from the reader and store into the array
	  for(i=0;i<16;i++){
		  currentTags[i][g] = key;
		}
	  }
	//check to see which tags are present
	for(k=0;k<7;k++){
	  for(i=0;i<16;i++){
	    if(currentTags[i][k] != tag1[i]){
		tagsPresent[0] = 0;
	    }else{tagsPresent[0] = 1;}
	  
	  if(currentTags[i][k] != tag2[i]){
		tagsPresent[1] = 0;
	    }else{tagsPresent[1] = 1;}
	  }
	  if(currentTags[i][k] != tag3[i]){
		tagsPresent[2] = 0;
	    }else{tagsPresent[2] = 1;}
	  
	  if(currentTags[i][k] != tag4[i]){
		tagsPresent[3] = 0;
	    }else{tagsPresent[3] = 1;}
	  
	  if(currentTags[i][k] != tag5[i]){
		tagsPresent[4] = 0;
	    }else{tagsPresent[4] = 1;}
	  
	  if(currentTags[i][k] != tag6[i]){
		tagsPresent[5] = 0;
	    }else{tagsPresent[5] = 1;}
	  
	  if(currentTags[i][k] != tag7[i]){
		tagsPresent[6] = 0;
	    }else{tagsPresent[6] = 1;}
	  }
	  for(i=0;i<7;i++){
	    if(tagsPresent[i] == 1){
		numTagsPresent++;
	    }
	  }
}
 

I suspect it has something to do with the way I initialized the 2 dimensional array.  (New to processing and Java) Thanks for the help!