How To Fix Missing SignalHandler Class Error

This is because JRE is used in your development IDE instead of JDK.

The following steps are for Eclipse only, so if you are using Netbeans, InteliJ or other, you will have to deal with this issue on your own.

1. Do mouse righ click on project and select Build Path / Configure Build Path,
2. Open Libraries tab and select JRE System Library, click on Edit button,
3. If you have JDK available on the list, choose it and press Finish and then Ok button. The problem should be fixed now.
4. If you do not have JDK on the list:

• Install JDK (OpenJDK, Oracle, or whatever),
• Restart Eclipse.

5. If installing JDK was not enough and you still have the same issue after restarting Eclipse, then:

• In Eclipse window select from menu Window / Preferences,
• Expand branch Java / Installed JREs,
• Click on Add button, choose Standard VM,
• Click on Directory and select the folder where you installed JDK (JARs list should appear after it's done),
• Click on Finish,
• From the list of Installed JREs list choose the newly added JDK and press Ok button.

6. After the workspace is rebuild the problem should be gone.