Caused by: java.security.UnrecoverableKeyException: Cannot recover key

If using Tomcat 6 and earlier, make sure the keystore password and the key password are same. If using Tomcat 7 and later, make sure they are the same or that the key password is specified in the server.xml file.

The private key password defined in your app/config is incorrect. First try verifying the the private key password by changing to another one as follows:

keytool -keypasswd -new changeit -keystore cacerts -storepass changeit -alias someapp -keypass password

The above example changes the password from password to changeit. This command will succeed if the private key password was password.

In order to not have the Cannot recover key exception, I had to apply the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files to the installation of Java that was running my application. Version 8 of those files can be found here or the latest version should be listed on this page. The download includes a file that explains how to apply the policy files.

Since JDK 8u151 it isn't necessary to add policy files. Instead the JCE jurisdiction policy files are controlled by a Security property called crypto.policy. Setting that to unlimited with allow unlimited cryptography to be used by the JDK. As the release notes linked to above state, it can be set by Security.setProperty() or via the java.security file. The java.security file could also be appended to by adding -Djava.security.properties=my_security.properties to the command to start the program as detailed here.

Since JDK 8u161 unlimited cryptography is enabled by default.