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javamavenjung

ArrayStoreException on JUNG VisualizationImageServer initialization

I'm trying to get a basic JUNG graph example running - I was able to get the following code to run in a standalone java program but when I put the same code in a server-side jar built using Maven, it fails with a ArrayStoreException on the VisualizationImageServer initialization:

public Response getGraph() throws IOException {
    //log.info("Starting graph rendering");
    try {
        DirectedSparseGraph<String, Number> g = new DirectedSparseGraph();
        String[] v = createVertices(10); 
        createEdges(v); 
        vv =  new VisualizationImageServer<String,Number>(new KKLayout<String,Number>(graph), new Dimension(600,600)); 
        renderGraph(vv);
        ...}

This line fails: 

        vv =  new VisualizationImageServer<String,Number>(new KKLayout<String,Number>(graph), new Dimension(600,600));

Error message snippet:

java.lang.ArrayStoreException: edu.uci.ics.jung.algorithms.layout.KKLayout
    at edu.uci.ics.jung.visualization.layout.ObservableCachingLayout.<init>(ObservableCachingLayout.java:50)
    at edu.uci.ics.jung.visualization.DefaultVisualizationModel.setGraphLayout(DefaultVisualizationModel.java:91)
    at edu.uci.ics.jung.visualization.DefaultVisualizationModel.<init>(DefaultVisualizationModel.java:74)
    at edu.uci.ics.jung.visualization.BasicVisualizationServer.<init>(BasicVisualizationServer.java:150)
    at edu.uci.ics.jung.visualization.VisualizationImageServer.<init>(VisualizationImageServer.java:40)
Solution

  • My best guess is that on your server side code, you have more than one version of jung that conflict with each other. On line 50 of ObservableCachingLayout in jung-visualization version 2.0, the delegate (KKLayout) is added to a org.apache.commons.collections15.Transformer[] array, because the KKLayout delegate is (supposed to be) an instance of a Transformer. Your array store exception that calls out the KKLayout as the problem makes me think that the earlier version 2.0 of ObservableCachingLayout is getting a version 2.1 or later KKLayout delegate (from jung-algorithms) that is not a Transformer, but is instead a com.google.common.base.Function. I can't verify that this is the actual problem, but I believe that this theory addresses a possible cause of the specific errors you are seeing.