Android：java.lang.NoClassDefFoundError

Question

我正在嘗試使用JTransforms庫在Android應用（使用最新的Android Studio）中計算數學函數（DoubleFFT_1D）。 我正在使用JTransforms 網站提供的.jar文件，並將其導入到項目中。 我已經嘗試了JTransforms修訂版2.4和3.1。 該代碼編譯沒有錯誤，但是當我到達實際的方法調用時，我收到以下錯誤消息：

09-07 17:30:11.369 E/JavaBinder: *** Uncaught remote exception!  (Exceptions are not yet supported across processes.)
                                 java.lang.NoClassDefFoundError: Failed resolution of: Lorg/jtransforms/fft/DoubleFFT_1D;
                                     at com.algoint.libzante.AutoCorrelation.compute(AutoCorrelation.java:66)
                                     at com.algoint.libzante.EstimateACF.estimateInSamplePeriods(EstimateACF.java:104)
                                     at <snip>
com.algoint.zante.BluetoothLeService.broadcastUpdate(BluetoothLeService.java:348)
                                     at com.algoint.zante.BluetoothLeService.access$700(BluetoothLeService.java:50)
                                     at com.algoint.zante.BluetoothLeService$1.onCharacteristicChanged(BluetoothLeService.java:243)
                                     at android.bluetooth.BluetoothGatt$1.onNotify(BluetoothGatt.java:438)
                                     at android.bluetooth.IBluetoothGattCallback$Stub.onTransact(IBluetoothGattCallback.java:399)
                                     at android.os.Binder.execTransact(Binder.java:453)
                                  Caused by: java.lang.ClassNotFoundException: Didn't find class "org.jtransforms.fft.DoubleFFT_1D" on path: DexPathList[[dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_9-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_8-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_7-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_6-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_5-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_4-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_3-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_2-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_1-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_0-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-json_simple-1.1_9ec115b071c72fb6edf2028f7a57e4ae60bb5a65-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-dropbox-android-sdk-1.5.4_74a0c4010a6328c8c6443241412fa9c5c398a9ab-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-achartengine-1.1.0_0238cc7eb0f70b6065b267fb6df8a8f6b48a5319-classes.dex"],nativeLibraryDirectories=[/data/app/com.algoint.zante-2/lib/arm64, /vendor/lib64, /system/lib64]]
                                     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                                     at com.android.tools.fd.runtime.IncrementalClassLoader$DelegateClassLoader.findClass(IncrementalClassLoader.java:90)
                                     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
                                     at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
                                     at com.algoint.libzante.AutoCorrelation.compute(AutoCorrelation.java:66) 
                                     at com.algoint.libzante.EstimateACF.estimateInSamplePeriods(EstimateACF.java:104) 
                                     at <snip>
com.algoint.zante.BluetoothLeService.broadcastUpdate(BluetoothLeService.java:348) 
                                     at com.algoint.zante.BluetoothLeService.access$700(BluetoothLeService.java:50) 
                                     at com.algoint.zante.BluetoothLeService$1.onCharacteristicChanged(BluetoothLeService.java:243) 
                                     at android.bluetooth.BluetoothGatt$1.onNotify(BluetoothGatt.java:438) 
                                     at android.bluetooth.IBluetoothGattCallback$Stub.onTransact(IBluetoothGattCallback.java:399) 
                                     at android.os.Binder.execTransact(Binder.java:453) 
                                    Suppressed: java.lang.ClassNotFoundException: Didn't find class "org.jtransforms.fft.DoubleFFT_1D" on path: DexPathList[[zip file "/data/app/com.algoint.zante-2/base.apk"],nativeLibraryDirectories=[/data/app/com.algoint.zante-2/lib/arm64, /vendor/lib64, /system/lib64]]
                                     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                                     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
                                     at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
                                            ... 12 more
                                        Suppressed: java.lang.ClassNotFoundException: Didn't find class "org.jtransforms.fft.DoubleFFT_1D" on path: DexPathList[[dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_9-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_8-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_7-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_6-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_5-classes.dex", dex file "/data/data/com.algoint.zante/files/instant-run/dex/slice-slice_4-classes.dex", dex file "/data/data/com.

我在源文件中按如下方式導入了jtransforms：

import org.jtransforms.fft.DoubleFFT_1D;

帶有正確的gradle條目：

apply plugin: 'java'
dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile files('libs/JTransforms-3.1-with-dependencies.jar')
}

以及相應的Android Studio依賴項設置：

該項目編譯沒有錯誤，並在以下行中引發了錯誤：

int n = 2 * nextPow2(x.length);
// Twice the number of elements are required: real and imaginary parts of the FFT are stored consecutively
double[] f = new double[2 * n];   
System.arraycopy(x, 0, f, 0, x.length);
// FFT
DoubleFFT_1D fft = new DoubleFFT_1D((long) n);  // ERROR ON THIS LINE
// Use "full" to avoid more machinations with symmetry
fft.realForwardFull(f);

引發錯誤時，n的值為1024，x的長度為500。我發現這兩個錯誤均同時存在：“ JTransforms-2.4.jar”和“ JTransforms-3.1-with-dependencies.jar”。 我認為原始項目是在Maven中編譯的，這有區別嗎？ 您能推薦任何解決方案嗎？ 謝謝。

Answer 1

最終，我找到了解決方案。 我忽略了.jar文件，只是將源代碼直接編譯到了項目中。 過程：-提取Jtransforms的完整git存儲庫，-將其從Maven項目轉換為Gradle項目（“ gradle init”），-將其作為模塊導入到我的項目中，然后-進行編譯。
我確實在刪除所有原始.jar文件（埋在目錄中）時遇到了一些麻煩，但是一旦完成，項目就可以編譯並運行良好。