#fixed code
                                public Object getReducedValue(Object ctx, Object thisValue, VariableResolverFactory factory) {
        try {
            if (!((Boolean) MVEL.eval(this.name, ctx, factory))) {
               throw new AssertionError("assertion failed in expression: " + new String(this.name));
            }
            else {
                return true;
            }
        }
        catch (ClassCastException e) {
            throw new CompileException("assertion does not contain a boolean statement");
        }
    }
#vulnerable code 
                                public Object getReducedValue(Object ctx, Object thisValue, VariableResolverFactory factory) {
        try {
            Boolean bool = (Boolean) MVEL.eval(this.name, ctx, factory);
            if (!bool) throw new AssertionError("assertion failed in expression: " + new String(this.name));
            return bool;
        }
        catch (ClassCastException e) {
            throw new CompileException("assertion does not contain a boolean statement");
        }
    } 
                            #location 4 
                            #vulnerability type NULL_DEREFERENCE