Add check for null as primary key to avoid: "JNI DETECTED ERROR IN APPLICATION: GetStringChars received null jstring"

[ghost]

Found this error while normal development. I haven't been able to reproduce it with what I think is the same data/situation.

version: 0.79.1
device: NEXUS 6 - Android 5.0.1

JNI DETECTED ERROR IN APPLICATION: GetStringChars received null jstring
in call to GetStringChars
from long io.realm.internal.Table.nativeFindFirstString(long, long, java.lang.String)
"IntentService[SyncService]" prio=5 tid=29 Runnable
| group="main" sCount=0 dsCount=0 obj=0x12fd89e0 self=0xac489400
| sysTid=22693 nice=0 cgrp=apps sched=0/0 handle=0xaf25e600
| state=R schedstat=( 249521400 80332037 348 ) utm=23 stm=1 core=1 HZ=100
| stack=0x9f85e000-0x9f860000 stackSize=1036KB
| held mutexes= "mutator lock"(shared held)
native: #00 pc 00004c58 /system/lib/libbacktrace_libc++.so (UnwindCurrent::Unwind(unsigned int, ucontext_)+23)
native: #1 pc 000034c1 /system/lib/libbacktrace_libc++.so (Backtrace::Unwind(unsigned int, ucontext_)+8)
native: #2 pc 002526ad /system/lib/libart.so (art::DumpNativeStack(std::_1::basic_ostream<char, std::1::char_traits >&, int, char const,
native: #3 pc 0023618b /system/lib/libart.so (art::Thread::Dump(std::1::basic_ostream<char, std::1::char_traits >&) const+162)
native: #4 pc 000b1215 /system/lib/libart.so (art::JniAbort(char const, char const)+620)
native: #5 pc 000b1945 /system/lib/libart.so (art::JniAbortF(char const, char const, ...)+68)
native: #6 pc 000b33df /system/lib/libart.so (art::ScopedCheck::CheckInstance(art::ScopedCheck::InstanceKind, jobject)+374)
native: #7 pc 000b3e43 /system/lib/libart.so (art::ScopedCheck::Check(bool, char const, ...) (.constprop.128)+762)
native: #8 pc 000bd59b /system/lib/libart.so (art::CheckJNI::GetStringChars(JNIEnv, jstring, unsigned char)+66)
native: #9 pc 000835d7 /data/app/de.komoot.android-1/lib/arm/libtightdb-jni.so (???)
native: #10 pc 00062d41 /data/app/de.komoot.android-1/lib/arm/libtightdb-jni.so (Java_io_realm_internal_Table_nativeFindFirstString+36)
native: #11 pc 0068d5c1 /data/dalvik-cache/arm/data@app@de.komoot.android-1@base.apk@classes.dex (
at io.realm.internal.Table.nativeFindFirstString(Native method)
at io.realm.internal.Table.findFirstString(Table.java:1401)
at io.realm.RealmRouteRealmProxy.copyOrUpdate(RealmRouteRealmProxy.java:704)
at java.lang.reflect.Method.invoke!(Native method)
at java.lang.reflect.Method.invoke(Method.java:372)
at io.realm.Realm.copyOrUpdate(Realm.java:1615)
at io.realm.Realm.copyToRealmOrUpdate(Realm.java:1207)
...

[kneth]

I can see that you have a data model which is using primary keys, and you have created an object and it going to copy it to your Realm. From the stack trace, I think that the field which is your primary key, is set to null. It is not supported to use null as value for a primary key, and we don't check it (we probably should - just to give you a better error message).

[intrications]

@kneth That was my problem. I had a primary key and I was accidentally trying to save an object created with the no-operator constructor.

A better error message would definitely have helped.

[VishwanathPatil]

I have similar problem , when jstring is passed as not being null , still this error shows up .
if(Data) char_Data = (*env)->GetStringUTFChars (env, Data, NULL);

[kneth]

@VishwanathPatil Does the error message vanish if you don't use a primary key?