Getting NullPointerException at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1198)

Question

Migrated from

    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.5</version>

to

    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.7</version>

Upon the execution of following instruction

VelocityContext vc = getVelocityContext(valuesMap);
StringWriter writer = new StringWriter();
Velocity.evaluate(vc, writer, "[generate email processor - event id = " + event.getId() + "]", bodyTemplate);

I am getting

java.lang.NullPointerException
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1198)
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1181)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1297)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1265)
        at org.apache.velocity.app.Velocity.evaluate(Velocity.java:180)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.generateMessage(GenerateMessageProcessor.java:1361)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.run(GenerateMessageProcessor.java:1155)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1198)
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1181)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1297)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1265)
        at org.apache.velocity.app.Velocity.evaluate(Velocity.java:180)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.generateMessage(GenerateMessageProcessor.java:1361)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.run(GenerateMessageProcessor.java:1155)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)

I am initializing the RuntimeSingleton once during the execution of application as below.

if(!RuntimeSingleton.isInitialized()) {
        RuntimeSingleton.init();
    }

Why am i getting the NullPointerException ?

Answer 1

In velocity (version 1.7). Properties have been externalize to a property file named velocity.property.

After specifying the below mentioned properties leaving all others with default values as per my requirement.The issue got resolved.

runtime.log = /tmp/velocity.log