Exception error in java when moving from ubuntu 12.04 to 10.04

Question

I am making a data acquisition software using Sparrow's Kmax . I am writing the code on my ubuntu 12.04 laptop. One of the methods I have created is the following

public double getValueFrom(String widgName) {//Read data from user input text fields
    KmaxWidget widg = tlsh.getKmaxWidget(widgName); 
    String str = widg.getProperty("TEXT");

    double num = 0;
    try {
        num = Double.parseDouble(str);
    }
    catch (Exception e) {
        tlsh.setProperty("STATUSSTR", "Attention! Channel and Energy must be double precision number. i.e. 10, 3.14 etc.");
        tlsh.showWarning("Choose a double precision number.");
        throw e;
    }
    return num; 
} // getValueFrom

When I compile the code on my laptop it goes without any error. When I copy my code to the ubuntu 10.04 desktop I get an exception code

unreported exception java.lang Exception: must be caught or declared to be thrown
throw e;
^

The first thing that crossed my mind was that they have different versions of java. Indeed that was true, so I updated 10.04's java, but again the same error occurs. Any idea on what might be wrong?

EDIT I also added throws Exception after method's arguments but whenever this method is called I get the error(on both systems)

unreported exception Exception; must be caught or declared to be thrown

Answer 1

The problem is coming because of :

 throw e;

Since you are throwing a java.lang.Exception object from your catch block your method signature has to include throws clause stating this and therefore your method signature now becomes (or else your compiler will complain):

  public double getValueFrom(String widgName) throws Exception

This change will resolve the problem.

Answer 2

As the exception says this function it should through the exception to parent class, so you define your function to through exeption like below

public double getValueFrom(String widgName) throws Exception
{
 // body
}