null 객체 참조에서 인터페이스 메소드 'java.lang.String java.security.PublicKey.getFormat()'을 호출하려고 시도했습니다.

Question

도움이 필요합니다 !!!

다음 예외를 제외하고 Android 5.0 Lollipop에서 내 앱이 작동하지 않습니다. 이전 버전에서도 작동합니다.

java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String java.security.PublicKey.getFormat()' on a null object reference 
at com.android.org.conscrypt.OpenSSLKey.fromPublicKey(OpenSSLKey.java:108) 
at com.android.org.conscrypt.OpenSSLSignature.engineInitVerify(OpenSSLSignature.java:170) 
at java.security.Signature$SignatureImpl.engineInitVerify(Signature.java:684) 
at java.security.Signature.initVerify(Signature.java:268) 
at com.android.vending.licensing.LicenseValidator.com.android.vending.licensing.LicenseCheckerCallback getCallback()(Unknown Source) 
void verify(java.security.PublicKey,int,java.lang.String,java.lang.String) 
void handleResponse(com.android.vending.licensing.Policy$LicenseResponse,com.android.vending.licensing.ResponseData) 
void handleApplicationError(com.android.vending.licensing.LicenseCheckerCallback$ApplicationErrorCode) 
at com.android.vending.licensing.LicenseChecker$ResultListener$2.void run()(Unknown Source) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:135) 
at android.os.HandlerThread.run(HandlerThread.java:61) 

누구든지 나에게 문제를 해결하는 방법을 알려 주시면 감사하겠습니다.

감사합니다, 카우 코우

Answer 1

추가 :

java.security.Security.insertProviderAt(new org.spongycastle.jce.provider.BouncyCastleProvider(), 1); 

before using PdfPKCS7 signatureProperties = af.verifySignature(signature); 



    FileInputStream is; 

       is = new FileInputStream(input); 

       java.security.Security.insertProviderAt(new org.spongycastle.jce.provider.BouncyCastleProvider(), 1); 


       //org.spongycastle.cms.CMSSignedData cmsSignedData = new CmsSignedData(stream); 



       try 


       { 

        PdfReader PDFReader = new PdfReader(is); 

       AcroFields af = PDFReader.getAcroFields(); 

       ArrayList<String> names = af.getSignatureNames(); 

       for(Iterator<String> i = names.iterator(); i.hasNext();) { 

        String signature = i.next(); 

        //obtain information about the signature 
        PdfPKCS7 signatureProperties = af.verifySignature(signature); 
        infoText.append(System.getProperty("line.separator") + signatureProperties.getDigestAlgorithmOid());