X-Git-Url: http://plrg.eecs.uci.edu/git/?p=jpf-core.git;a=blobdiff_plain;f=src%2Fmain%2Fgov%2Fnasa%2Fjpf%2Flistener%2FVariableConflictTracker.java;h=04182946a09aa2d4b066949a18696091447d2dbc;hp=561a4091ce9e71d7e337d36ba607c563d5410a6e;hb=fe051f890e5b90b33902d3c9c252bc587ca4bffe;hpb=8c32849672197006bb409246f70dc60ffcb97324

diff --git a/src/main/gov/nasa/jpf/listener/VariableConflictTracker.java b/src/main/gov/nasa/jpf/listener/VariableConflictTracker.java
index 561a409..0418294 100644
--- a/src/main/gov/nasa/jpf/listener/VariableConflictTracker.java
+++ b/src/main/gov/nasa/jpf/listener/VariableConflictTracker.java
@@ -93,7 +93,7 @@ public class VariableConflictTracker extends ListenerAdapter {
           byte type  = getType(ti, executedInsn);
           String value = getValue(ti, executedInsn, type);
           //System.out.println("\n\n" + ti.getStackTrace() + "\n\n");
-          String writer = getWriter(ti.getStack());
+          String writer = getWriter(ti.getStack());         
           // Just return if the writer is not one of the listed apps in the .jpf file
           if (writer == null)
             return;
@@ -132,6 +132,14 @@ public class VariableConflictTracker extends ListenerAdapter {
         // Conflict is declared when:
         // 1) Current writer != previous writer, e.g., App1 vs. App2
         // 2) Current value != previous value, e.g., "locked" vs. "unlocked"
+        if (current.value == null) {
+
+          StringBuilder sb = new StringBuilder();
+          sb.append("Conflict between apps " + current.writer + " and " + writer + ": ");
+          sb.append("Current value cannot be read (null value)... Please double check with your app output!");
+          Instruction nextIns = ti.createAndThrowException("java.lang.RuntimeException", sb.toString());
+          ti.setNextPC(nextIns);
+        }
         if (!current.value.equals(value)) {
 
           StringBuilder sb = new StringBuilder();