Big memory usage spike

Newbie & Debugging Questions
#1

So I’ve been working on my tile map editor and I’ve been having some issues with massive memory usage spikes when you attempt to save the map

Here’s the code I have to save the world to a file. Hopefully this should all make sense:


	public static void requestWorldSave(World w) throws FileNotFoundException {
		JFrame frame = new JFrame();
		frame.setLocation(0, 0);
		frame.setResizable(false);
		frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
		frame.setLayout(null);
		frame.pack();

		Dimension d = new Dimension(400, 400);

		frame.setPreferredSize(d);
		frame.setMaximumSize(d);
		frame.setMinimumSize(d);
		
		JFileChooser jfc = new JFileChooser();
		int r = jfc.showSaveDialog(frame);
		if (r == JFileChooser.APPROVE_OPTION) {
			File f = jfc.getSelectedFile();
			String contents = "";
			
			WorldInfo wi = w.getInfo();
			
//Loop through all the tiles in the world
			for (int x = 0; x < wi.nChunksX * Chunk.chunkW; x++) {
				for (int y = 0; y < wi.nChunksY * Chunk.chunkH; y++) {
					contents += w.getTile(x, y).getID() + " ";
				}
			}
			
			contents = FileEncrypter.encryptString(contents);
			
			PrintWriter pr = new PrintWriter(f);
			pr.write(contents);
			pr.close();
			
//			f = null;
//			contents = "";
//			contents = null;
//			pr = null;
//			jfc = null;
//			
//			System.gc();
		}
	}

You’ll see the commented out lines of code was what i tried to reduce to memory usage but it didn’t seem to work.

The memory spikes from around 40mb to 400mb, i admit 400mb is manageable and not a great deal but I’d at least like to get to the bottom of why this is happening.

Thanks :slight_smile: