IOException: Cannot run program "dot"

PROBLEM:
IOException: Cannot run program "dot"

[WARNING] Javadoc Warnings
[WARNING] java.io.IOException: Cannot run program "dot": java.io.IOException: error=2, No such file or directory
[WARNING] at java.lang.ProcessBuilder.start(ProcessBuilder.java:460)
[WARNING] at java.lang.Runtime.exec(Runtime.java:593)
[WARNING] at java.lang.Runtime.exec(Runtime.java:466)
[WARNING] at org.umlgraph.doclet.UmlGraphDoc.runGraphviz(UmlGraphDoc.java:131)
[WARNING] at org.umlgraph.doclet.UmlGraphDoc.generatePackageDiagrams(UmlGraphDoc.java:95)
[WARNING] at org.umlgraph.doclet.UmlGraphDoc.start(UmlGraphDoc.java:63)
[WARNING] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[WARNING] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[WARNING] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[WARNING] at java.lang.reflect.Method.invoke(Method.java:597)
[WARNING] at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:269)
[WARNING] at com.sun.tools.javadoc.DocletInvoker.start(DocletInvoker.java:143)
[WARNING] at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:340)
[WARNING] at com.sun.tools.javadoc.Start.begin(Start.java:128)
[WARNING] at com.sun.tools.javadoc.Main.execute(Main.java:41)
[WARNING] at com.sun.tools.javadoc.Main.main(Main.java:31)

SOLUTION:
sudo apt-get install graphviz