public String getJavaVersion() {
    return javaVersion;
  }
The Java version, as returned by the {@code java.version} system property.
Examples for valid values (for Oracle/OpenJDK) are {@code "1.6.0_22"} and {@code "1.7.0_07"}.

@return the Java version, as returned by the {@code java.version} system property
spock-core/src/main/java/spock/util/environment/Jvm.java