NullPointerException

[duki97]

Sometimes I get some errors. The app doesn't crash and shows the PDF, but these errors are displayed in the console.
It doesn't happen always, only sometimes randomly.
1.------------------------------------------
E/FrameEvents( 5755): updateAcquireFence: Did not find frame.
D/EGL_emulation( 5755): app_time_stats: avg=516.62ms min=13.77ms max=1963.59ms count=4
E/FrameEvents( 5755): updateAcquireFence: Did not find frame.
E/com.shockwave.pdfium.PdfiumCore( 5755): mContext may be null
W/System.err( 5755): java.lang.NullPointerException: Attempt to invoke virtual method 'long java.lang.Long.longValue()' on a null object reference
W/System.err( 5755): at com.shockwave.pdfium.PdfiumCore.renderPageBitmap(PdfiumCore.java:312)
W/System.err( 5755): at com.github.barteksc.pdfviewer.PdfFile.renderPageBitmap(PdfFile.java:295)
W/System.err( 5755): at com.github.barteksc.pdfviewer.RenderingHandler.proceed(RenderingHandler.java:109)
W/System.err( 5755): at com.github.barteksc.pdfviewer.RenderingHandler.handleMessage(RenderingHandler.java:66)
W/System.err( 5755): at android.os.Handler.dispatchMessage(Handler.java:106)
W/System.err( 5755): at android.os.Looper.loopOnce(Looper.java:201)
W/System.err( 5755): at android.os.Looper.loop(Looper.java:288)
W/System.err( 5755): at android.os.HandlerThread.run(HandlerThread.java:67)
2.------------------------------------------
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
D/com.shockwave.pdfium.PdfiumCore(10208): Starting PdfiumAndroid 1.9.2
I/PlatformViewsController(10208): Hosting view in view hierarchy for platform view: 58
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
W/Parcel (10208): Expecting binder but got null!
2
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
E/com.shockwave.pdfium.PdfiumCore(10208): mContext may be null
W/System.err(10208): java.lang.NullPointerException: Attempt to invoke virtual method 'long java.lang.Long.longValue()' on a null object reference
W/System.err(10208): at com.shockwave.pdfium.PdfiumCore.renderPageBitmap(PdfiumCore.java:312)
W/System.err(10208): at com.github.barteksc.pdfviewer.PdfFile.renderPageBitmap(PdfFile.java:295)
W/System.err(10208): at com.github.barteksc.pdfviewer.RenderingHandler.proceed(RenderingHandler.java:109)
W/System.err(10208): at com.github.barteksc.pdfviewer.RenderingHandler.handleMessage(RenderingHandler.java:66)
W/System.err(10208): at android.os.Handler.dispatchMessage(Handler.java:106)
W/System.err(10208): at android.os.Looper.loopOnce(Looper.java:210)
W/System.err(10208): at android.os.Looper.loop(Looper.java:299)
W/System.err(10208): at android.os.HandlerThread.run(HandlerThread.java:67)
D/com.shockwave.pdfium.PdfiumCore(10208): Starting PdfiumAndroid 1.9.2
I/PlatformViewsController(10208): Hosting view in view hierarchy for platform view: 59
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
W/Parcel (10208): Expecting binder but got null!
32
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
D/com.shockwave.pdfium.PdfiumCore(10208): Starting PdfiumAndroid 1.9.2
I/PlatformViewsController(10208): Hosting view in view hierarchy for platform view: 60
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
W/Parcel (10208): Expecting binder but got null!
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
E/com.shockwave.pdfium.PdfiumCore(10208): mContext may be null
W/System.err(10208): java.lang.NullPointerException: Attempt to read from field 'java.util.Map com.shockwave.pdfium.PdfDocument.mNativePagesPtr' on a null object reference in method 'void com.shockwave.pdfium.PdfiumCore.renderPageBitmap(com.shockwave.pdfium.PdfDocument, android.graphics.Bitmap, int, int, int, int, int, boolean)'
W/System.err(10208): at com.shockwave.pdfium.PdfiumCore.renderPageBitmap(PdfiumCore.java:312)
W/System.err(10208): at com.github.barteksc.pdfviewer.PdfFile.renderPageBitmap(PdfFile.java:295)
W/System.err(10208): at com.github.barteksc.pdfviewer.RenderingHandler.proceed(RenderingHandler.java:109)
W/System.err(10208): at com.github.barteksc.pdfviewer.RenderingHandler.handleMessage(RenderingHandler.java:66)
W/System.err(10208): at android.os.Handler.dispatchMessage(Handler.java:106)
W/System.err(10208): at android.os.Looper.loopOnce(Looper.java:210)
W/System.err(10208): at android.os.Looper.loop(Looper.java:299)
W/System.err(10208): at android.os.HandlerThread.run(HandlerThread.java:67)
D/com.shockwave.pdfium.PdfiumCore(10208): Starting PdfiumAndroid 1.9.2
I/PlatformViewsController(10208): Hosting view in view hierarchy for platform view: 61
E/FrameEvents(10208): updateAcquireFence: Did not find frame.
W/Parcel (10208): Expecting binder but got null!.