How To Run Eclipse Debugger Mode to See Order of Operations?

Question

In a previous question I had asked about recursion one of the responses recommended that I use debugger mode to see the order of operations. I had a few more order of operations questions, but figured I should use the debugger to run it instead of asking silly questions each time.

I ran the application in "Debug As" -> "Java Application" in Eclipse, and it just runs the program in a normal console giving me the same result as if I were to run it.

This is the program in question(Just what I am using to test Debug, I don't have questions regarding this actual app):

public class main {
public static void main(String [] args){
System.out.println(fact(5));

}

public void fact()
{
fact(5);
}

public static int fact(int n)
{
if(n == 1){
    return 1;
}
return n * (fact(n-1) + 5);
}
}

In Debug mode it just provided me with "1145", which is the same thing that the normal "Run" mode provides me.

I wanted to see the actual step by step instructions that are being fed into the JVM, which is what I gathered that Debug is supposed to do.

I read online instructions on how to Debug applications, and that tutorial had different options in Eclipse then mine, such as "toggle breakpoint", which I do not have in the most recent version of Eclipse.

Can someone please point me to a direction as to how to get Eclipse to show me step-by-step operations.

It seems learning how to debug is an art of it's own. I was thinking it would just say 5*(5-1) etc, until it gets to the final answer — LearnIT, Jun 05 '13 at 18:20

score 2 · Answer 1 · answered Jun 05 '13 at 18:13

2

You need to add debug points in your code.see how to debug

answered Jun 05 '13 at 18:13

Sanjaya Liyanage

4,706
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Thanks, that looks like a solid step-by-step. – LearnIT Jun 05 '13 at 18:21

score 2 · Accepted Answer · answered Jun 05 '13 at 18:13

2

In Eclipse you double-click in the left margin beside a line and it will set a breakpoint at that line and mark it.

When you run in debug mode, it will stop when it gets to a line with a breakpoint and you can look at the stack and variable values and what-not. A whole new perspective will try to pop up when it hits that breakpoint that has lots of windows with interesting info.

answered Jun 05 '13 at 18:13

Lee Meador

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Wow, it's not nearly as simple as I thought. – LearnIT Jun 05 '13 at 18:24
Sometimes its easier to just print or log messages and look at the output. Sometimes that's extremely tedious. – Lee Meador Jun 05 '13 at 18:25

score 2 · Answer 3 · answered Jun 05 '13 at 18:14

2

If you double-click in the left margin, you can set a breakpoint. It will appear as a blue dot.

answered Jun 05 '13 at 18:14

betseyb

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How To Run Eclipse Debugger Mode to See Order of Operations?

3 Answers3