SSL Java java.io.IOException: Invalid keystore format

I faced with the same problem when load keystore with the following code:

KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
Resource resource = new ClassPathResource(file);
trustStore.load(resource.getInputStream(), password.toCharArray());

It turned out to be the JDK issue, it doesn't work with jre1.8.0_25. when I upgrade JDK version to the latest jre1.8.0_121, it works.

Your file is invalid. You have to import a JKS keystore file and not a txt one. You have to use the keytool to create your keystore file and then import this file.

I had exactly the same issue. Indeed, the keystore file was invalid and not related to the JDK//JRE version. The problem in my case was caused by Maven. I was using the following option in my pom file:

<resources>
        <resource>
            <directory>src/main/resources</directory>
            <filtering>true</filtering>
        </resource>
    </resources>

The "true" value in the filtering was messing with the key file. Therefore, the keyfile that was available in my classpath when Spring run was not exactly the same I had under my directory "src/main/resources" and that caused the Invalid Keystore Format exception. When I tested with keytool I was using the one under the "resources" folder so that was misleading the real issue.

Solving the issue: in your pom.xml file, change the value for "filtering" to "false". Another way of solving the issue was to specify explicitly the location of the keystore in the application.properties file. So instead of:

server.ssl.key-store: classpath:keystore.jks

I used

server.ssl.key-store: keystore/keystore.jks