When the principal name in the cache and the principal doing as request are not the same the following occurs:
java.io.IOException: Invalid name length in principal name.
        at sun.security.krb5.internal.ccache.CCacheInputStream.readPrincipal(CCacheInputStream.java:130)
        at sun.security.krb5.internal.ccache.FileCredentialsCache.load(FileCredentialsCache.java:161)
        at sun.security.krb5.internal.ccache.FileCredentialsCache.acquireInstance(FileCredentialsCache.java:73)
        at sun.security.krb5.internal.ccache.CredentialsCache.getInstance(CredentialsCache.java:78)
        at sun.security.krb5.internal.tools.Kinit.<init>(Kinit.java:282)
        at sun.security.krb5.internal.tools.Kinit.main(Kinit.java:116)