GridDataset.open(path) blows up on Android w/cdm-core:5.3.2, works with netcdf4:4.6.11

[jskubick]

I recently posted a question to StackOverflow that was resolved, along with a suggestion that I switch from using netcdf4:4.6.11 to cdm-core:5.3.2 (I'm using it purely to parse GOES-16 data files).

As the immediate result of switching to cdm-core, cleaning, and re-synchronizing Gradle, the call to GridDataset.open(path) is now blowing up (full details at end).

Original Gradle artifact:

implementation('edu.ucar:netcdf4:4.6.11') {
    exclude group: 'com.amazonaws', module: 'aws-java-sdk-s3'
}

Present Gradle artifact:

implementation('edu.ucar:cdm-core:5.3.2') {
    exclude group: 'com.amazonaws', module: 'aws-java-sdk-s3'
}

The line that used to work, and now blows up:

GridDataset gds = GridDataset.open(file.getAbsolutePath());

The data file itself is being fetched from NOAA's AWS S3 bucket, and saved as an Android temp file with "abi-l2-acmc-" as its prefix, and ".nc" as its suffix.

Example path that used to work, but now blows up:

/data/user/0/pantherkitty.launchspotter/cache/abi-l2-acmc-8973509210811327440.nc

Logcat dump follows at the very end.

I'm taking a stab in the dark, but I know netCDF-Java required an ENORMOUS amount of refactoring to make it usable with Android a couple of years ago. The text of the error message ("exception from call site #31 bootstrap method") makes me wonder whether some chunk of code that's needed by Android might have ended up getting accidentally removed (or, if it's a ground-up rewrite, didn't get put in)?

If it matters, I'm testing it using the x86 Android emulator with API 28 (Android 9)

2020-05-30 23:05:11.638 14719-14719/pantherkitty.launchspotter E/AndroidRuntime: FATAL EXCEPTION: main
    Process: pantherkitty.launchspotter, PID: 14719
    java.lang.RuntimeException: Caught exception while opening GridDataset
        at pantherkitty.launchspotter.CloudMaskData.create(CloudMaskData.java:44)
        at pantherkitty.launchspotter.MapsActivity.updateOverlay(MapsActivity.java:127)
        at pantherkitty.launchspotter.MapsActivity$2.onReceive(MapsActivity.java:74)
        at androidx.localbroadcastmanager.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:313)
        at androidx.localbroadcastmanager.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:121)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.io.IOException: java.lang.BootstrapMethodError: Exception from call site #31 bootstrap method
        at ucar.nc2.NetcdfFile.open(NetcdfFile.java:384)
        at ucar.nc2.dataset.NetcdfDataset.openProtocolOrFile(NetcdfDataset.java:824)
        at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:478)
        at ucar.nc2.dataset.NetcdfDataset.acquireDataset(NetcdfDataset.java:633)
        at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:85)
        at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:71)
        at pantherkitty.launchspotter.CloudMaskData.create(CloudMaskData.java:41)
        at pantherkitty.launchspotter.MapsActivity.updateOverlay(MapsActivity.java:127) 
        at pantherkitty.launchspotter.MapsActivity$2.onReceive(MapsActivity.java:74) 
        at androidx.localbroadcastmanager.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:313) 
        at androidx.localbroadcastmanager.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:121) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
     Caused by: java.lang.BootstrapMethodError: Exception from call site #31 bootstrap method
        at ucar.nc2.Group.<init>(Group.java:832)
        at ucar.nc2.Group.<init>(Group.java:37)
        at ucar.nc2.Group$Builder.build(Group.java:1132)
        at ucar.nc2.NetcdfFile.makeRootGroup(NetcdfFile.java:2026)
        at ucar.nc2.NetcdfFile.<init>(NetcdfFile.java:2548)
        at ucar.nc2.NetcdfFile.open(NetcdfFile.java:782)
        at ucar.nc2.NetcdfFile.open(NetcdfFile.java:381)
        at ucar.nc2.dataset.NetcdfDataset.openProtocolOrFile(NetcdfDataset.java:824) 
        at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:478) 
        at ucar.nc2.dataset.NetcdfDataset.acquireDataset(NetcdfDataset.java:633) 
        at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:85) 
        at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:71) 
        at pantherkitty.launchspotter.CloudMaskData.create(CloudMaskData.java:41) 
        at pantherkitty.launchspotter.MapsActivity.updateOverlay(MapsActivity.java:127) 
        at pantherkitty.launchspotter.MapsActivity$2.onReceive(MapsActivity.java:74) 
        at androidx.localbroadcastmanager.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:313) 
        at androidx.localbroadcastmanager.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:121) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
     Caused by: java.lang.ClassCastException: Bootstrap method returned null
        at ucar.nc2.Group.<init>(Group.java:832) 
        at ucar.nc2.Group.<init>(Group.java:37) 
        at ucar.nc2.Group$Builder.build(Group.java:1132) 
        at ucar.nc2.NetcdfFile.makeRootGroup(NetcdfFile.java:2026) 
        at ucar.nc2.NetcdfFile.<init>(NetcdfFile.java:2548) 
        at ucar.nc2.NetcdfFile.open(NetcdfFile.java:782) 
        at ucar.nc2.NetcdfFile.open(NetcdfFile.java:381) 
        at ucar.nc2.dataset.NetcdfDataset.openProtocolOrFile(NetcdfDataset.java:824) 
        at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:478) 
        at ucar.nc2.dataset.NetcdfDataset.acquireDataset(NetcdfDataset.java:633) 
        at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:85) 
        at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:71) 
        at pantherkitty.launchspotter.CloudMaskData.create(CloudMaskData.java:41) 
        at pantherkitty.launchspotter.MapsActivity.updateOverlay(MapsActivity.java:127) 
        at pantherkitty.launchspotter.MapsActivity$2.onReceive(MapsActivity.java:74) 
        at androidx.localbroadcastmanager.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:313) 
        at androidx.localbroadcastmanager.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:121) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

[lesserwhirls]

Let me start by saying I do not do any Android development myself, so it might take some trial and error to figure this one out. There are a couple of things that come to mind, but first would be to ask what sourceCompatibility and targetCompatibility you are setting, if any, in your gradle build, and what version of java you are using to compile.

Second, the cdm-core artifact does not include aws-java-sdk-s3 as a dependency, so you won't need to exclude it.

[jskubick]

OK, that seems to have fixed it. I wasn't explicitly setting the value for either sourceCompatibility or targetCompatibility. I changed both to explicitly specify 1.8, and it seems to be working now.

For the sake of historical documentation:

Android studio is using Java installed (probably by AS itself) to c:\Program Files\Android\Android Studio\jre. Output of java -version:

openjdk version "1.8.0_212-release"
OpenJDK Runtime Environment (bu9ild 1.8.0_212-release-1586-b04)
OpenJDK 64-Bit Server VM (build 25.212-b04, mixed mode)

On the config panel for Project Structure -> Modules -> app -> Properties, I had the following values:

Compile Sdk Version = 29 (API 29: Android 10.0(Q))
Build Tools Version = 29.0.1
Source Compatibility = (blank), I changed it to 1.8

Target Compatibility = (blank), I changed it to 1.8