UI: Fix update checker TLS version

Since BinDiff does not ship with a full JDK, but with a stripped down JRE,
SSL/TLS config files are omitted.

This change forces TLS v1.2 for the update check to prevent
"Could not check for update. The update site returned no data." errors.

PiperOrigin-RevId: 377357578
Change-Id: If1d6d6b85f70d26ab56c411707e78ba2c40777ff

Author: cblichmann

java/ui/src/main/java/com/google/security/zynamics/bindiff/BinDiff.java

@@ -95,6 +95,13 @@ private BinDiff() {}
       // Do nothing. macOS integration will be sub-optimal but there's nothing we can meaningfully
       // do here.
     }
+    try {
+      // For the update check: force the use of a recent TLS version. TLS 1.3 is not generally
+      // usable yet.
+      System.setProperty("https.protocols", "TLSv1.2");
+    } catch (final SecurityException e) {
+      /* Ignore */
+    }
   }
 
   public static boolean isDesktopIntegrationDone() {

java/zylib/src/main/java/com/google/security/zynamics/zylib/gui/license/UpdateCheckHelper.java

@@ -112,6 +112,11 @@ protected void runExpensiveCommand() throws Exception {
           parent, "Could not check for updates. The update site is unavailable.");
       return;
     }
+    if (e != null) {
+      CMessageBox.showWarning(
+          parent, "Could not check for updates: " + e.getMessage());
+      return;
+    }
 
     if (lines.isEmpty()) {
       CMessageBox.showWarning(