public static int getMajorVersion() {
        return MAJOR_VERSION;
    }
Get the major version code. This means we can do things like
<code>if (getMajorVersion() &lt; JAVA_14)</code>.

@return a code comparable to the JAVA_XX codes in this class
@see #JAVA_13
@see #JAVA_14
@see #JAVA_15
@see #JAVA_16
@see #JAVA_17
@see #JAVA_18
core/src/main/java/org/apache/shiro/util/JavaEnvironment.java