小编use*_*405的帖子

当我尝试使用发送电子邮件时，出现以下错误javax.mail-api：

Caused by: java.lang.LinkageError: loader constraint violation: loader (instance of org/apache/felix/framework/BundleWiringImpl$BundleClassLoaderJava5) previously initiated loading for a different type with name "javax/mail/Session"
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
        at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.findClass(BundleWiringImpl.java:2279)
        at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1501)
        at org.apache.felix.framework.BundleWiringImpl.access$400(BundleWiringImpl.java:75)
        at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1955)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        at com.sun.mail.util.PropUtil.getBooleanSessionProperty(PropUtil.java:86)
        at javax.mail.internet.MimeMessage.initStrict(MimeMessage.java:320)
        at javax.mail.internet.MimeMessage.<init>(MimeMessage.java:195)
        at sendEmail(manage.java:216)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.camel.component.bean.MethodInfo.invoke(MethodInfo.java:408)
        at org.apache.camel.component.bean.MethodInfo$1.doProceed(MethodInfo.java:279)
        at org.apache.camel.component.bean.MethodInfo$1.proceed(MethodInfo.java:252)

码：

Public void sendEmail() {
    String to = "abc@abc.com";
    String from = "efg@efg.com";
    final String username = "abc@abc.com";
    final …

在C++中,

i = ++++j;

在代码中工作正常,但是当我使用时,

i = j++++;

我收到以下错误:

Operand for operator "++" must be an lvalue.

为什么我收到此错误？