/* * Copyright 2002-2007 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *      http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package org.springframework.core;/** * Internal helper class used to find the Java/JDK version * that Spring is operating on, to allow for automatically * adapting to the present platform's capabilities. * * 
Note that Spring requires JVM 1.4 or higher, as of Spring 2.5. * * @author Rod Johnson * @author Juergen Hoeller * @author Rick Evans */public abstract class JdkVersion {    /**     * Constant identifying the 1.3.x JVM (JDK 1.3).     */    public static final int JAVA_13 = 0;    /**     * Constant identifying the 1.4.x JVM (J2SE 1.4).     */    public static final int JAVA_14 = 1;    /**     * Constant identifying the 1.5 JVM (Java 5).     */    public static final int JAVA_15 = 2;    /**     * Constant identifying the 1.6 JVM (Java 6).     */    public static final int JAVA_16 = 3;    /**     * Constant identifying the 1.7 JVM (Java 7).     */    public static final int JAVA_17 = 4;    public static final int JAVA_18 = 4;    private static final String javaVersion;    private static final int majorJavaVersion;    static {        javaVersion = System.getProperty("java.version");        // version String should look like "1.4.2_10"        if(javaVersion.indexOf("1.8.") != -1){            majorJavaVersion = JAVA_18;        }else if (javaVersion.indexOf("1.7.") != -1) {            majorJavaVersion = JAVA_17;        }        else if (javaVersion.indexOf("1.6.") != -1) {            majorJavaVersion = JAVA_16;        }        else if (javaVersion.indexOf("1.5.") != -1) {            majorJavaVersion = JAVA_15;        }        else {            // else leave 1.4 as default (it's either 1.4 or unknown)            majorJavaVersion = JAVA_14;        }    }    /**     * Return the full Java version string, as returned by     * System.getProperty("java.version").     * @return the full Java version string     * @see System#getProperty(String)     */    public static String getJavaVersion() {        return javaVersion;    }    /**     * Get the major version code. This means we can do things like     * if (getMajorJavaVersion() < JAVA_14).     * @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     */    public static int getMajorJavaVersion() {        return majorJavaVersion;    }    /**     * Convenience method to determine if the current JVM is at least Java 1.4.     * @return true if the current JVM is at least Java 1.4     * @see #getMajorJavaVersion()     * @see #JAVA_14     * @see #JAVA_15     * @see #JAVA_16     * @see #JAVA_17     */    public static boolean isAtLeastJava14() {        return true;    }    /**     * Convenience method to determine if the current JVM is at least     * Java 1.5 (Java 5).     * @return true if the current JVM is at least Java 1.5     * @see #getMajorJavaVersion()     * @see #JAVA_15     * @see #JAVA_16     * @see #JAVA_17     */    public static boolean isAtLeastJava15() {        return getMajorJavaVersion() >= JAVA_15;    }    /**     * Convenience method to determine if the current JVM is at least     * Java 1.6 (Java 6).     * @return true if the current JVM is at least Java 1.6     * @see #getMajorJavaVersion()     * @see #JAVA_16     * @see #JAVA_17     */    public static boolean isAtLeastJava16() {        return getMajorJavaVersion() >= JAVA_16;    }}

在spring源码中有这样一个类会检查当前运行的jdk版本，他会把1.8当做小于1.5的版本处理，所以在源码加入这些即可，希望能帮助到后来人