yatagan posted:

Here's a better way, remember which was last filled in by the user.

mister_gosh posted:

Ok, after trying for 8+ hours, I thought I better try here. I have two .war files which reference a couple of external jars in a Tomcat application.

I keep getting java.lang.NoClassDefFoundError: com/neva/COMException

Which, I believe, means it is not finding com.neva.COMException and likely none of the other external jars.

So, tried a number of attempts to get my war to read it, each one more desperate than the next:

1. modified setclasspath.bat in tomcat to include my jars in the classpath
2. modified catalina.properties (same as above)
3. deleted tomcat work directory
4. numerous machine restarts
5. numerous tomcat service restarts (after each configuration change)
6. put external jars directly in java home and next to rt.jar
7. put the jars in numerous and countless locations in the tomcat area including webapps/ROOT/lib
8. modified war's manifest to specify a classpath (and was careful to add the required end of line)

Nothing seems to work, and I'm very frustrated and would be very grateful if anyone has any ideas. Thanks!

MEAT TREAT posted:

Try putting the jars in the tomcat/lib folder.

epswing posted:

mister_gosh said he's got two war files, so two web apps. Isn't MEAT TREAT's suggestion exactly what tomcat/lib is for (ie multiple webapps having access to the same set of jars)?

epswing posted:

mister_gosh said he's got two war files, so two web apps. Isn't MEAT TREAT's suggestion exactly what tomcat/lib is for (ie multiple webapps having access to the same set of jars)?

epswing posted:

Does tomcat override by filename or by what's inside the jar?

epswing posted:

I'm writing about 100,000 lines to an HttpServletResponse:

code:

List<String> lines = ... // 100,000 elements, about 60 chars each, so about 6mb
String newline = System.getProperty("line.separator");

response.setContentType("text/plain; charset=utf-8");
PrintWriter out = response.getWriter();

long start = System.currentTimeMillis();

for (String line : lines) {
  out.write(line);
  out.write(newline);
}

logger.info("time: " + (System.currentTimeMillis() - start) + " ms"); // 10455 ms

out.flush();
out.close();

This takes about 10 seconds, running both the server (tomcat) and client (firefox) locally. Would you expect it to take that long? I thought perhaps 100k calls to out.write was a bit much, so using StringBuilder I concatenated all the elements in the list and did one big out.write(buffer.toString()), and that also took about 10 seconds.

I'm going to start playing with maybe setting the content length in advance, or trying different content types, but would you expect a response of this size to take 10 seconds? I don't think I'm bandwidth-limited, because we're only talking about 6mb / 10s = 600k/s here, and I'd expect to be able to hit a faster speed than that when everything is local.

Internet Janitor posted:

korofrog: Perhaps you could remove the "convert" button entirely?

If you attach keylisteners to your textfields, you can update the other fields live:

code:

private final JTextArea ft = new JTextArea();
private final JTextArea in = new JTextArea();
private final JTextArea cm = new JTextArea();
private final JTextArea m = new JTextArea();

...

ft.addKeyListener(new KeyListener() {
	public void keyReleased(KeyEvent e) {
		try {
			double n = Double.parseDouble(ft.getText());
			in.setText("" + (12 * n));
			cm.setText("" + (30.48 * n));
			m.setText("" + (.3048 * n));
		}
		catch (NumberFormatException nfe) {
			in.setText("---");
			cm.setText("---");
			m.setText("---");
		}
	}
	public void keyTyped(KeyEvent e) {}
	public void keyPressed(KeyEvent e) {}
});

And so forth for the other fields. I don't think you can use the keyTyped() event, because we also want to update the fields when you delete a character. In my experience KeyListener events are not very consistent across platforms, so your mileage may vary.

IMlemon posted:

I need to create a (very simplified) message passing interface for Java processes so that you can do all kinds of parralel magic. Yeah right. Anyways, I know how to use threads and using those would be much easier but sadly, I have to use processes. Now, I googled this up a little bit and found processBuilder and runtime.exec thingies, but both of those seem to execute OS native commands, which isn't what im looking for. I want the process to execute Java code, like threads do.

Am I missing something very obvious and there's a way I can easily stuff some Java code to a process and tell the sucker to execute it? Or should I just say, whatever, and use threads? I don't have much time for this assignment .

I am in posted:

I'll give a hint about the culprit. If you redo the code above to use this brace style

code:

if(condition) {
  doSomething();
}

you should see the problem quite quickly.

Flobbster posted:

Telling him to switch to an inferior brace style is a terrible way of pointing him to his problem.

korofrog posted:

Ok, I'm working on a different part of my project and haven't gotten to the conversion panel yet and I'm running into a small problem.

code:

public boolean checkFields()
		{
			if ((poolLengthField.getText().compareTo("")<1)	||
				(poolWidthField.getText().compareTo("")<1)	||
				(poolDepthField.getText().compareTo("")<1))
			{
				if (poolLengthField.getText().compareTo("")<1)
				{
					poolLengthField.setBackground(Color.RED);
				}//end if statement
				
				if ((poolWidthField.getText().compareTo("")<1));
				{
					poolWidthField.setBackground(Color.RED);
				}//end if statement
				
				if ((poolDepthField.getText().compareTo("")<1))
				{
					poolDepthField.setBackground(Color.RED);
				}//end if statement
				
				poolStatus.setText("Please fill out all fields");
				return false;
			}//end if statement
			else
			{
				poolLengthField.setBackground(Color.WHITE);
				poolWidthField.setBackground(Color.white);
				poolDepthField.setBackground(Color.WHITE);
				poolStatus.setText("");
				return true;
			}//end else statement

epswing posted:

code:

import java.util.ArrayList;
import java.util.List;

public class Test {
	
	public static void main(String[] args) {
		
		List<Integer> list = new ArrayList<Integer>();
		list.add(1);
		list.add(2);
		list.add(3);
		
		Test t = new Test();
		t.method(list);
	}
	
	public void method(Object o) {
		System.out.println("method one: " + o);
	}
	
	public void method(List<Object> o) {
		System.out.println("method two: " + o);
	}
}

code:

method one: [1, 2, 3]

Why does Java run the first overloaded method, rather than the second? I mean I know List<Integer> is an Object but

TRex EaterofCars posted:

The generics. If you put List<Integer> instead of List<Object> it works how you want. If you want to refer to a List of anything just use List and ignore the parametric warnings.

epswing posted:

Why does Java run the first overloaded method, rather than the second? I mean I know List<Integer> is an Object but

rjmccall posted:

Flobbster posted:

This is what wildcards are for. If you want a method that takes a List of anything, do this:

code:

	public void method(List<?> o) {
		System.out.println("method two: " + o);
	}

Flobbster posted:

This is what wildcards are for. If you want a method that takes a List of anything, do this:

JDK SE posted:

As a general rule, the default load factor (.75) offers a good tradeoff between time and space costs. Higher values decrease the space overhead but increase the lookup cost (reflected in most of the operations of the HashMap class, including get and put). The expected number of entries in the map and its load factor should be taken into account when setting its initial capacity, so as to minimize the number of rehash operations. If the initial capacity is greater than the maximum number of entries divided by the load factor, no rehash operations will ever occur.

stubblyhead posted:

Say I have a compiled class HelloWorld.class. To run it from the command line, I would type java HelloWorld. Why can I not use java HelloWorld.class ? Unix is usually very particular about filenames, so it surprises me that using the full filename causes errors.

stubblyhead posted:

Secondly, is it possible to make the class file executable on its own, similar to how you can write a perl script, set the execute flag and add #!/usr/bin/perl at the top?

rjmccall posted:

1. Consider whether you can reasonably just add this as an int field to Page.

quote:

2. You're doing a lot of unnecessary re-lookups. This actually hashes the tag name twice:

code:

if (tagWeights.containsKey(tags[i].getName())) {
  Integer weight = tagWeights.get(tags[i].getName());

Just call get() and check the result for null. Similarly with your pageWeights lookup.

quote:

3. Profile.

quote:

4. If Page is hashed/compared by object identity, consider using an IdentityHashMap. It's actually a totally different hash implementation from HashMap which is (1) substantially faster and (2) substantially less memory hungry.

quote:

5. Consider making the values of pageWeights a mutable record of some kind so that you don't have to create new objects all the time.