title: Paypal rest sdk- internal service error has occurred error
body: <p>I am trying to execute transaction using paypal rest sdk.</p>
  
  <p>I am trying in this way same as sdk documentation :.</p>
  
  <p>OAuthTokenCredential tokenCredential =
        new OAuthTokenCredential("", "");</p>
  
  <pre><code>String accessToken = tokenCredential.getAccessToken();
  
  Address billingAddress = new Address();
  billingAddress.setLine1("52 N Main ST");
  billingAddress.setCity("Johnstown");
  billingAddress.setCountryCode("US");
  billingAddress.setPostalCode("43210");
  billingAddress.setState("OH");
  
  CreditCard creditCard = new CreditCard();
  creditCard.setNumber("4417119669820331");
  creditCard.setType("visa");
  creditCard.setExpireMonth("11");
  creditCard.setExpireYear("2018");
  creditCard.setCvv2("874");
  creditCard.setFirstName("Joe");
  creditCard.setLastName("Shopper");
  creditCard.setBillingAddress(billingAddress);
  
  AmountDetails amountDetails = new AmountDetails();
  amountDetails.setSubtotal("7.41");
  amountDetails.setTax("0.03");
  amountDetails.setShipping("0.03");
  
  Amount amount = new Amount();
  amount.setTotal("7.47");
  amount.setCurrency("USD");
  amount.setDetails(amountDetails);
  
  Transaction transaction = new Transaction();
  transaction.setAmount(amount);
  transaction.setDescription("This is the payment transaction description.");
  
  List&lt;Transaction&gt; transactions = new ArrayList&lt;Transaction&gt;();
  transactions.add(transaction);
  
  FundingInstrument fundingInstrument = new FundingInstrument();
  fundingInstrument.setCreditCard(creditCard);
  
  List&lt;FundingInstrument&gt; fundingInstruments = new ArrayList&lt;FundingInstrument&gt;();
  fundingInstruments.add(fundingInstrument);
  
  Payer payer = new Payer();
  payer.setFundingInstruments(fundingInstruments);
  payer.setPaymentMethod("credit_card");
  
  Payment payment = new Payment();
  payment.setIntent("sale");
  payment.setPayer(payer);
  payment.setTransactions(transactions);
  
  Payment createdPayment = payment.create(accessToken);
  
  Payment executePayment = Payment.get(accessToken, "PAY-34629814WL663112AKEE3AWQ");
  
  PaymentExecution paymentExecution = new PaymentExecution();
  paymentExecution.setPayerId("7E7MGXCWTTKK2");
  
  Payment newPayment = executePayment.execute(accessToken, paymentExecution);
  </code></pre>
  
  <p>But I am getting exception as </p>
  
  <pre><code>Caused by: com.paypal.exception.HttpErrorException: Error code : 500 with response : 
  {"name":"INTERNAL_SERVICE_ERROR","message":"An internal service error has occurred","information_link":
  "https://developer.paypal.com/webapps/developer/docs/api/#INTERNAL_SERVICE_ERROR","debug_id":"7a7f0k30b2719"}
          at com.paypal.core.HttpConnection.execute(HttpConnection.java:108)
          at com.paypal.core.rest.PayPalResource.execute(PayPalResource.java:321)
          ... 214 more
  </code></pre>
  
  <p>Anybody can tell me why I am getting this error?</p>
  
  <p>Thanks,</p>