Expose JVM exceptions (#566)

* Wrap spark exceptions per #472

* Extra tests for JvmException
Code styling per guidelines from review by @imback82 in #541

* Add JvmBridge doc link

Co-authored-by: Steve Suh <suhsteve@gmail.com>

* Fix per code guidelines

Co-authored-by: Steve Suh <suhsteve@gmail.com>

* Fix cref link

* Formatting

Co-authored-by: Steve Suh <suhsteve@gmail.com>

* Add license header

Co-authored-by: Steve Suh <suhsteve@gmail.com>

Author: thrixton

src/csharp/Microsoft.Spark.E2ETest/IpcTests/JvmBridgeTests.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using Microsoft.Spark.Sql;
+using Xunit;
+
+namespace Microsoft.Spark.E2ETest.IpcTests
+{
+    [Collection("Spark E2E Tests")]
+    public class JvmBridgeTests
+    {
+        private readonly SparkSession _spark;
+
+        public JvmBridgeTests(SparkFixture fixture)
+        {
+            _spark = fixture.Spark;
+        }
+
+        [Fact]
+        public void TestInnerJvmException()
+        {
+            try
+            {
+                _spark.Sql("THROW!!!");
+            }
+            catch (Exception ex)
+            {
+                Assert.NotNull(ex.InnerException);
+                Assert.IsType<JvmException>(ex.InnerException);
+                Assert.False(string.IsNullOrWhiteSpace(ex.InnerException.Message));
+            }
+        }
+    }
+}

src/csharp/Microsoft.Spark/Interop/Ipc/JvmBridge.cs

@@ -189,7 +189,7 @@ private object CallJavaMethod(
                         args);
                     _logger.LogError(errorMessage);
                     _logger.LogError(jvmFullStackTrace);
-                    throw new Exception(errorMessage);
+                    throw new Exception(errorMessage, new JvmException(jvmFullStackTrace));
                 }
 
                 char typeAsChar = Convert.ToChar(inputStream.ReadByte());

src/csharp/Microsoft.Spark/JvmException.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+namespace Microsoft.Spark
+{
+    /// <summary>
+    /// Contains the message returned from the <see cref="Interop.Ipc.JvmBridge"/> on an error.
+    /// </summary>
+    public class JvmException : Exception
+    {
+        public JvmException(string message) 
+            : base(message)
+        {
+        }
+    }
+}