# Nodetool Throws NullPointerException

## Problem

A NullPointerException is thrown when you run `nodetool`. For example:

```console
java.lang.NullPointerException
    at org.apache.cassandra.config.DatabaseDescriptor.getDiskFailurePolicy(DatabaseDescriptor.java:1881)
    at org.apache.cassandra.utils.JVMStabilityInspector.inspectThrowable(JVMStabilityInspector.java:82)
    at org.apache.cassandra.io.util.FileUtils.<clinit>(FileUtils.java:79)
    at org.apache.cassandra.utils.FBUtilities.getToolsOutputDirectory(FBUtilities.java:824)
    at org.apache.cassandra.tools.NodeTool.printHistory(NodeTool.java:200)
    at org.apache.cassandra.tools.NodeTool.main(NodeTool.java:168)
```

## Solution

NullPointerException may have more than one cause. When you run the nodetool utility, the exception may indicate
an unsupported Java version installed on your machine. Nodetool supports Java 7 and 8.

1. Check your Java version with the `java --version` command.
2. If nodetool does not support your version, replace it with Java 7 or 8.