Android 4 and Java 1.7 prefer TLSv1.2 provider (#4089)

* java 1.7 TLV v1.2 support

* simplify TLSv1.2 vs TLS selection logic

* tighten up version checks

* cleanup

okhttp/src/main/java/okhttp3/internal/platform/AndroidPlatform.java

@@ -23,12 +23,14 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.net.InetSocketAddress;
 import java.net.Socket;
+import java.security.NoSuchAlgorithmException;
 import java.security.Security;
 import java.security.cert.Certificate;
 import java.security.cert.TrustAnchor;
 import java.security.cert.X509Certificate;
 import java.util.List;
 import javax.annotation.Nullable;
+import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLPeerUnverifiedException;
 import javax.net.ssl.SSLSocket;
 import javax.net.ssl.SSLSocketFactory;
@@ -427,4 +429,20 @@ class AndroidPlatform extends Platform {
       return trustManager.hashCode() + 31 * findByIssuerAndSignatureMethod.hashCode();
     }
   }
+
+  @Override public SSLContext getSSLContext() {
+    if (Build.VERSION.SDK_INT >= 16 && Build.VERSION.SDK_INT < 22) {
+      try {
+        return SSLContext.getInstance("TLSv1.2");
+      } catch (NoSuchAlgorithmException e) {
+        // fallback to TLS
+      }
+    }
+
+    try {
+      return SSLContext.getInstance("TLS");
+    } catch (NoSuchAlgorithmException e) {
+      throw new IllegalStateException("No TLS provider", e);
+    }
+  }
 }

okhttp/src/main/java/okhttp3/internal/platform/Platform.java

@@ -124,8 +124,8 @@ public class Platform {
     return null;
   }
 
-  public void connectSocket(Socket socket, InetSocketAddress address,
-      int connectTimeout) throws IOException {
+  public void connectSocket(Socket socket, InetSocketAddress address, int connectTimeout)
+      throws IOException {
     socket.connect(address, connectTimeout);
   }
 
@@ -176,8 +176,10 @@ public class Platform {
     X509TrustManager trustManager = trustManager(sslSocketFactory);
 
     if (trustManager == null) {
-      throw new IllegalStateException("Unable to extract the trust manager on " + Platform.get()
-          + ", sslSocketFactory is " + sslSocketFactory.getClass());
+      throw new IllegalStateException("Unable to extract the trust manager on "
+          + Platform.get()
+          + ", sslSocketFactory is "
+          + sslSocketFactory.getClass());
     }
 
     return buildCertificateChainCleaner(trustManager);
@@ -265,6 +267,16 @@ public class Platform {
   }
 
   public SSLContext getSSLContext() {
+    String jvmVersion = System.getProperty("java.specification.version");
+    if ("1.7".equals(jvmVersion)) {
+      try {
+        // JDK 1.7 (public version) only support > TLSv1 with named protocols
+        return SSLContext.getInstance("TLSv1.2");
+      } catch (NoSuchAlgorithmException e) {
+        // fallback to TLS
+      }
+    }
+
     try {
       return SSLContext.getInstance("TLS");
     } catch (NoSuchAlgorithmException e) {