?
Solved

NewStringUTF gives memory leak?

Posted on 2000-02-16
8
Medium Priority
?
1,444 Views
Last Modified: 2012-06-21
I have a thread running in native code which needs to call a static Java method with a jstring parameter.

Code:

jstring            jstr;
char            szTxt[MAX_DEBUG_OUT_LEN];
jclass            cls;
jmethodID      mid;

// Init code cut away here...

jstr = tmp_env->NewStringUTF(szTxt);
tmp_env->CallStaticVoidMethod( cls, mid, jstr );


The problem I got is that the NewStringUTF seems to allocate memory, and I don't know how to deallocate it. The JVM doesn't seem to take care of it, "delete" does not work, and ReleaseStringUTFChars does not work either (they crash the app ).

How do I get rid of the memory?
0
Comment
Question by:zingo
  • 4
  • 3
8 Comments
 
LVL 5

Expert Comment

by:mbormann
ID: 2526836
clicl around this thread
http://sourceware.cygnus.com/ml/cygwin/1998-10/msg00615.html

>>>(they crash the app )

What platform Windows /Unixes?
0
 

Author Comment

by:zingo
ID: 2526871
The platform is Windows and I am using Visual J++.
0
What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

 
LVL 5

Expert Comment

by:mbormann
ID: 2526910
I think taht from that site the code to free jstring is

const char *str = (*env)->GetStringUTFChars(env, Your_jstring, 0);
(*env)->ReleaseStringUTFChars(env, Your_jstring, str);

please let me know if this helps you out.
0
 

Author Comment

by:zingo
ID: 2527343
nope, it still leaks like a bottom-less bucket...

According to the documentation and examples from Sun, ReleaseStringUTFChars is used together with GetStringUTFChars. I've never seen it used with NewStringUTF.

0
 

Accepted Solution

by:
ChristerH earned 400 total points
ID: 2527350
Use this code to delete the reference, then the JVM's garbage collector will deallocate the memory.

tmp_env->DeleteLocalRef(jstr);
 
 
0
 

Author Comment

by:zingo
ID: 2527362
Thanks ChristerH, you saved my day!
0
 
LVL 5

Expert Comment

by:mbormann
ID: 2530054
Oops ,and a thanks from me too, what we did was we had no need to track these as our .exe used to call Java object and go off.

I will bookmark this question.As they say u never stop learning.
:~)
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Java had always been an easily readable and understandable language.  Some relatively recent changes in the language seem to be changing this pretty fast, and anyone that had not seen any Java code for the last 5 years will possibly have issues unde…
Java Flight Recorder and Java Mission Control together create a complete tool chain to continuously collect low level and detailed runtime information enabling after-the-fact incident analysis. Java Flight Recorder is a profiling and event collectio…
Viewers will learn about the regular for loop in Java and how to use it. Definition: Break the for loop down into 3 parts: Syntax when using for loops: Example using a for loop:
This theoretical tutorial explains exceptions, reasons for exceptions, different categories of exception and exception hierarchy.
Suggested Courses
Course of the Month15 days, 6 hours left to enroll

840 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question