When we try to post an Assignment, its throwing null pointer exception.

 VelocityViewServlet : Error processing a template for path ''
Invocation of method 'getAssignmentStatus' in class com.sun.proxy.$Proxy163 threw exception java.lang.NullPointerException at /vm/assignment/chef_assignments_list_assignments.vm[line 486, column 78]

java.lang.NullPointerException
at org.sakaiproject.assignment.impl.AssignmentServiceImpl.getAssignmentStatus(AssignmentServiceImpl.java:1521)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:283)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy163.getAssignmentStatus(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:389)
at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:378)
at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:270)
at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:262)
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:342)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:366)
at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:106)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
at org.apache.velocity.Template.merge(Template.java:328)
at org.apache.velocity.Template.merge(Template.java:235)
at org.apache.velocity.tools.view.servlet.VelocityViewServlet.performMerge(VelocityViewServlet.java:805)
at org.apache.velocity.tools.view.servlet.VelocityViewServlet.mergeTemplate(VelocityViewServlet.java:762)
at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doRequest(VelocityViewServlet.java:555)
at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doGet(VelocityViewServlet.java:509)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)