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  1. #1
    Moondazz is offline Member
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    Default java.lang.nullpointerexception when using maps with arraylist

    I have posted this question in another site also, since I am desperately looking for help with this issue. Im a beginner in Java and I have created the following program, where the operations is class which consists of different fields and acts like a struct in C. The code is as follows:

    Java Code:
    public class operations extends DefFunctionHandler {  
        public Integer stre;  
        public Integer functii;  
        public String nmee;  
        public Integer funcigroup;  
        public Integer sourcee;  
    }  
          
    public void execute(String x) {  
         ArrayList<operations> ops= new ArrayList<operations>();  
         for(int i=0; i< functi.size();i++){  
             operations op = new operations();  
             op.stre = str.get(i);  
             op.functii = functi.get(i);  
             op.funcigroup = functigroup.get(i);  
             op.nmee = nme.get(i);  
             op.sourcee = src.get(i);  
             ops.add(op);  
        }  
          
         Map<ArrayList<String>,ArrayList<operations>> obs = new HashMap<ArrayList<String>, ArrayList<operations>>();  
         obs.put(nme, ops);  
           
         for(operations o: obs.get(x)){  
             System.out.println(o.functii);  
         }
    I get a nullpointexception error on the line for(operations o : obs.get(x)). Can anyone tell me what the problem is?
    Last edited by Moondazz; 06-12-2013 at 05:22 PM.

  2. #2
    DarrylBurke's Avatar
    DarrylBurke is offline Member
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    Default Re: java.lang.nullpointerexception when using maps with arraylist

    Cross posted
    java.lang.nullpointerexception when using maps with arraylist (Beginning Java forum at JavaRanch)

    Did also cross post an earlier related question on the Ranch and SO.

    db
    If you're forever cleaning cobwebs, it's time to get rid of the spiders.

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