package org.slf4j.log4j12;
   
   import java.lang.reflect.Method;
   
   import org.slf4j.helpers.Util;
   
   public class VersionUtil {
       // code was compiled under Java 8 or later
       static final int MINIMAL_VERSION = 8;
  
      static public int getJavaMajorVersion() {
          String javaVersionString = Util.safeGetSystemProperty("java.version");
          return getJavaMajorVersion(javaVersionString);
      }
  
      static public int getJavaMajorVersion(String versionString) {
          if (versionString == null)
              return MINIMAL_VERSION;
          if (versionString.startsWith("1.")) {
              return versionString.charAt(2) - '0';
          } else {
              // we running under Java 9 or later
              try {
                  Method versionMethod = Runtime.class.getMethod("version");
                  Object versionObj = versionMethod.invoke(null);
                  Method majorMethod = versionObj.getClass().getMethod("major");
                  Integer resultInteger = (Integer) majorMethod.invoke(versionObj);
                  return resultInteger.intValue();
              } catch (Exception e) {
                  return MINIMAL_VERSION;
              }
          }
      }
  }