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NewStringUTF gives memory leak?

Posted on 2000-02-16
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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?
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Question by:zingo
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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?
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Expert Comment

by:mbormann
ID: 2526841
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Author Comment

by:zingo
ID: 2526871
The platform is Windows and I am using Visual J++.
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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.
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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.

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Accepted Solution

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ChristerH earned 100 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);
 
 
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Author Comment

by:zingo
ID: 2527362
Thanks ChristerH, you saved my day!
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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.
:~)
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