Can transient keywords mark a method?

问题

In a java class java.util.Locale, I find that the keyword transient marked a method.

 public final class Locale
    implements Cloneable, Serializable
{
    private static class LocaleNameGetter
        implements sun.util.LocaleServiceProviderPool.LocalizedObjectGetter
    {

        public transient String getObject(LocaleNameProvider localenameprovider, Locale locale, String s, Object aobj[])
        {
            if(!$assertionsDisabled && aobj.length != 2)
                throw new AssertionError();
            int i = ((Integer)aobj[0]).intValue();
            String s1 = (String)aobj[1];
            switch(i)
            {
            case 0: // '\0'
                return localenameprovider.getDisplayLanguage(s1, locale);

            case 1: // '\001'
                return localenameprovider.getDisplayCountry(s1, locale);

            case 2: // '\002'
                return localenameprovider.getDisplayVariant(s1, locale);
            }
            if(!$assertionsDisabled)
                throw new AssertionError();
            else
                return null;
        }

Can someone tell me why can this be?

回答1:

No it can't, it's only valid for fields. You seem to get your source from .class by decompiling. This is the decompiler bug, if you take a look at java.lang.reflect.Modifier src you will see that transient and varargs have the same value

public static final int TRANSIENT        = 0x00000080;
...
static final int VARARGS   = 0x00000080;

for a field 0x00000080 means transient, for a method (your case) it means varargs. This is how getObject looks like in java.util.Locale src

public String getObject(LocaleNameProvider localeNameProvider,
                        Locale locale, 
                        String key,
                        Object... params) {   <-- varargs

In .class (bytecode) varargs is represented by Object[] as the last parameter + modifier bit 7 = 1 (0x80). I guess the decompiler is old and simply does not know about varargs which is since Java 1.5 so it printed it as transient.

回答2:

If this code has been decompiled it is most likely a result of this: Why Java methods with varargs identified as transient?

I am quoting from there:

Sort of an answer can be found in the code of javassist AccessFlag

public static final int TRANSIENT = 0x0080; public static final int VARARGS = 0x0080; It appears both have the same values. And since transient means nothing for methods, while varargs means nothing for fields, it is ok for them to be the same.

回答3:

transient can only be applied to member variables and not to methods so there is a problem here.

Looking at the variable names in your code - things like String s and Object[] aboj - it looks like this source has been generated by decompiling the relevant .class file.

I think there is a bug in whichever decompiler you're using which is erroneously adding transisent to the method declaration.

回答4:

Java documentation states that transient keyword is only applied to instance variables so this doesn´t make any sense

回答5:

This has to be a bug. Or some buggy revision? transient is only applied on variables. Can you provide a link where you see that?

来源：https://stackoverflow.com/questions/16233910/can-transient-keywords-mark-a-method

标签

java

transient