Java11Exec: Fix that EOF is replaced by newline.

deploy/aws/java11Exec/src/main/java/poseidon/App.java

@@ -11,16 +11,12 @@ import com.amazonaws.services.lambda.runtime.events.APIGatewayV2WebSocketEvent;
 import com.google.gson.Gson;
 import com.google.gson.JsonObject;
 
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.Base64;
 import java.util.Map;
-import java.util.NoSuchElementException;
-import java.util.Scanner;
 
 // AwsFunctionRequest contains the java files that needs to be executed.
 class AwsFunctionRequest {
@@ -147,16 +143,29 @@ public class App implements RequestHandler<APIGatewayV2WebSocketEvent, APIGatewa
 
         output.join();
         error.join();
-        this.sendMessage(WebSocketMessageType.WebSocketExit, null, p.exitValue());
+        this.sendMessage(WebSocketMessageType.WebSocketExit, null, p.waitFor());
     }
 
     // scanForOutput reads the passed stream and forwards it via the WebSocket connection.
     private void scanForOutput(Process p, InputStream stream, WebSocketMessageType type) {
-        Scanner outputScanner = new Scanner(stream);
-        while (p.isAlive() || outputScanner.hasNextLine()) {
-            try {
-                this.sendMessage(type, outputScanner.nextLine() + "\n", null);
-            } catch (NoSuchElementException ignored) {}
+        BufferedReader br = new BufferedReader(new InputStreamReader(stream));
+        StringBuilder s = new StringBuilder();
+        int nextByte;
+
+        try {
+            while ((nextByte = br.read()) != -1) {
+                char c = (char) nextByte;
+                s.append(c);
+
+                if (c == '\n') {
+                    this.sendMessage(type, s.toString(), null);
+                    s = new StringBuilder();
+                }
+            }
+        } catch (IOException ignored) {}
+
+        if (!s.toString().isEmpty()) {
+            this.sendMessage(type, s.toString(), null);
         }
     }
 

deploy/aws/java11Exec/src/test/java/poseidon/AppTest.java

@@ -41,6 +41,16 @@ public class AppTest {
           "    }\n" +
           "}").getBytes(StandardCharsets.UTF_8));
 
+  static final String MathContentWithoutTrailingNewline = Base64.getEncoder().encodeToString(
+          ("package org.example;\n" +
+          "\n" +
+          "public class RecursiveMath {\n" +
+          "\n" +
+          "    public static void main(String[] args) {\n" +
+          "        System.out.print(\"Mein Text\");\n" +
+          "    }\n" +
+          "}").getBytes(StandardCharsets.UTF_8));
+
   @Test
   public void successfulResponse() {
     APIGatewayProxyResponseEvent result = getApiGatewayProxyResponse(RecursiveMathContent);
@@ -62,6 +72,20 @@ public class AppTest {
     assertEquals(expectedOutput, out.toString());
   }
 
+  @Test
+  public void outputWithoutTrailingNewline() {
+    ByteArrayOutputStream out = setupStdOutLogs();
+    APIGatewayProxyResponseEvent result = getApiGatewayProxyResponse(MathContentWithoutTrailingNewline);
+    restoreStdOutLogs();
+
+    assertEquals(200, result.getStatusCode().intValue());
+    String expectedOutput =
+            "{\"type\":\"stdout\",\"data\":\"Mein Text\"}\n" +
+            "{\"type\":\"exit\",\"data\":0}\n";
+    assertEquals(expectedOutput, out.toString());
+  }
+
+
   private PrintStream originalOut;
   private ByteArrayOutputStream setupStdOutLogs() {
     originalOut = System.out;