RFR: JDK-8198393: Instrumentation.retransformClasses() throws NullPointerException when handling a zero-length array

[Alex Menkov]

Hi Serguei,

updated webrev:
http://cr.openjdk.java.net/~amenkov/retransformClassesZeroLength/webrev.02/

- updated copyright in th eInstrumentationImpl.java
- removed inused imports in the test


On 03/26/2018 14:31, serguei.spitsyn at oracle.com wrote:
> Hi Alex,
> 
> It looks good to me.
> 
> A couple of questions:
> 
>   - How does the test fail with the unfixed code?

As described in the jira issue:
  stdout: [FATAL ERROR in native method: processing of -javaagent failed
];
  stderr: [java.lang.reflect.InvocationTargetException
         at 
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native 
Method)
         at 
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
         at 
java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
         at java.base/java.lang.reflect.Method.invoke(Method.java:564)
         at 
java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:513)
         at 
java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:525)
Caused by: java.lang.NullPointerException
         at 
java.instrument/sun.instrument.InstrumentationImpl.retransformClasses0(Native 
Method)
         at 
java.instrument/sun.instrument.InstrumentationImpl.retransformClasses(InstrumentationImpl.java:167)
         at 
RetransformClassesZeroLength$Agent.premain(RetransformClassesZeroLength.java:77)
         ... 6 more
*** java.lang.instrument ASSERTION FAILED ***: "numClasses != 0" at 
line: 1146

--alex

> 
>   - It seems, the following imports in the test are not needed:
> 
>    34 import java.io.IOException;
>    . . .
>    43 import java.util.Arrays;
>    . . .
>    45 import jdk.test.lib.Utils;
>    46 import jdk.test.lib.process.ExitCode;
>    47 import jdk.test.lib.process.OutputAnalyzer;
> 
> Thanks,
> Serguei
> 
> 
> On 3/22/18 16:18, Alex Menkov wrote:
>> Hi all,
>>
>> Please take a look at a simple fix for
>> https://bugs.openjdk.java.net/browse/JDK-8198393
>> webrev: 
>> http://cr.openjdk.java.net/~amenkov/retransformClassesZeroLength/webrev/
>>
>> --alex
>