Fix Java exception serialization (#10568)

java/runtime/src/main/java/io/ray/runtime/exception/RayActorException.java

@@ -12,4 +12,12 @@ public class RayActorException extends RayException {
     super("The actor died unexpectedly before finishing this task.");
   }
 
+  public RayActorException(String message) {
+    super(message);
+  }
+
+  public RayActorException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
 }

java/runtime/src/main/java/io/ray/runtime/exception/RayWorkerException.java

@@ -9,4 +9,12 @@ public class RayWorkerException extends RayException {
     super("The worker died unexpectedly while executing this task.");
   }
 
+  public RayWorkerException(String message) {
+    super(message);
+  }
+
+  public RayWorkerException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
 }

java/runtime/src/main/java/io/ray/runtime/exception/UnreconstructableException.java

@@ -11,7 +11,7 @@ import io.ray.api.id.ObjectId;
  */
 public class UnreconstructableException extends RayException {
 
-  public final ObjectId objectId;
+  public ObjectId objectId;
 
   public UnreconstructableException(ObjectId objectId) {
     super(String.format(
@@ -20,4 +20,12 @@ public class UnreconstructableException extends RayException {
     this.objectId = objectId;
   }
 
+  public UnreconstructableException(String message) {
+    super(message);
+  }
+
+  public UnreconstructableException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
 }