Exception Catching

Question

I was wondering what strategies people use to know what exceptions to try and catch? I would like to be able to know what potential exceptions may be thrown by a method or any method it calls etc.
For example I was recently working with DefaultMutableTreeNode.insertNodeInto() method, and got the following: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1 > 0
at java.util.Vector.insertElementAt(Vector.java:551)
at javax.swing.tree.DefaultMutableTreeNode.insert(DefaultMutableTreeNode.java:177)
at javax.swing.tree.DefaultTreeModel.insertNodeInto(DefaultTreeModel.java:218)
at CheckTree.CheckTreeModel.addNode(CheckTreeModel.java:88)
Now I can look up Vector.insertElementAt() and see what exceptions it could potentially raise. However if I look @ insertNodeInto() in the JavaDocs, it doesn't list any potential exceptions that may be raised, nor does it tell me that it uses Vector.insertElementAt().
Since A. I don't always have all the source code I need to dig through everything I call to see what may cause a problem,
and B. I don't want to have to go through 3000+ lines of source code just to go, oh look someMethod() can raise a DivideByZero exception! I better be prepared to catch it in my function 6 calls up the ladder.
So I'm guessing there is a happy medium when it comes to knowing what to look for.
I know a large part of good code it is making sure your passing sane arguments in your method calls, but when working with new API's it's not always easy to tell what will end up being sane and logical and what will be inappropriate garbage. (Especially with how lacking the JavaDocs can be).
So like I said I'm wondering what strategies work well for people?

Answer 1

OKAY Let's take a look at a quote from the first post.
For example I was recently working with DefaultMutableTreeNode.insertNodeInto() method, and got the following: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1 > 0
at java.util.Vector.insertElementAt(Vector.java:551)
at javax.swing.tree.DefaultMutableTreeNode.insert(DefaultMutableTreeNode.java:177)
at javax.swing.tree.DefaultTreeModel.insertNodeInto(DefaultTreeModel.java:218)
at CheckTree.CheckTreeModel.addNode(CheckTreeModel.java:88) You all should be able to recognize a call stack printed in resoponse to an unhandled exception.
Let's take a look at the line in bold. Yes I was mistaken about the object calling insertNodeInto().
But there is a lot of useful information in the callstack, a quick inspection of the callstack reveals
A. the insertNodeInto called was a method of DefaultTreeModel.
B. The exception was raised in insertElementAt()
C. insertElementAt() is called by DefaultMutableTreeNode.insert() which is called by DefaultTreeModel.insertNodeInto().
Here is a direct copy of DefaultTreeModel,insertNodeInto() java doc:
insertNodeInto
public void insertNodeInto(MutableTreeNode newChild,
MutableTreeNode parent,
int index)Invoked this to insert newChild at location index in parents children. This will then message nodesWereInserted to create the appropriate event. This is the preferred way to add children as it will create the appropriate event.
notice a lack of mention of "ArrayIndexOutOfBoundsException" There is a very simple reason for this.
It is because the exception is raised not by insertNodeInto, but by insertElementAt().
I am not stating that the documentation for insertNodeInto() is wrong. It is merely not warning me that I may get an exception generated by a method called my a method it itself falls. For which I do not blame it, because insertNodeInto does NOT directly raise the exception.
I was simply asking what people do to handle exceptions that are generally unforseeable.