diff --git a/test/lib-test/jdk/test/lib/process/ProcessToolsLastLineTest.java b/test/lib-test/jdk/test/lib/process/ProcessToolsLastLineTest.java
new file mode 100644
index 0000000000000..696f76f0f1e78
--- /dev/null
+++ b/test/lib-test/jdk/test/lib/process/ProcessToolsLastLineTest.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8303697
+ * @summary Test verifies that ProcessTools.startProcess() print all lines even the last line doesn't end with '\n'
+ * @library /test/lib
+ * @run main ProcessToolsLastLineTest
+ */
+
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.Asserts;
+
+public class ProcessToolsLastLineTest {
+
+    static void test(String output) throws Exception {
+        final StringBuffer sb = new StringBuffer();
+        Process p = ProcessTools.startProcess("process",
+                ProcessTools.createJavaProcessBuilder(ProcessToolsLastLineTest.class.getName(), output),
+                line -> { sb.append(line);});
+        p.waitFor();
+        String expectedOutput = output.replace("\n", "");
+        Asserts.assertEQ(sb.toString(), expectedOutput);
+    }
+
+    public static void main(String[] args) throws Exception {
+
+        // The line which exceeds internal StreamPumper buffer (256 bytes)
+        String VERY_LONG_LINE = "X".repeat(257);
+        if (args.length > 0) {
+            System.out.print(args[0]);
+        } else {
+            test("\n");
+            test("\nARG1");
+            test("\nARG1\n");
+            test("ARG1\n");
+            test("ARG1");
+            test("ARG1\nARG2");
+            test("ARG1\nARG2\n");
+            test("\nARG1\nARG2\n");
+            test("\nARG1\n" + VERY_LONG_LINE + "\nARG2\n");
+            test("\nARG1\n" + VERY_LONG_LINE);
+            test("\nARG1\n" + VERY_LONG_LINE + VERY_LONG_LINE + VERY_LONG_LINE + "\nARG2\n");
+            test("\nARG1\n" + VERY_LONG_LINE + VERY_LONG_LINE + VERY_LONG_LINE);
+
+        }
+
+    }
+}
diff --git a/test/lib/jdk/test/lib/process/StreamPumper.java b/test/lib/jdk/test/lib/process/StreamPumper.java
index ad62f6c300a90..63775f7d62c56 100644
--- a/test/lib/jdk/test/lib/process/StreamPumper.java
+++ b/test/lib/jdk/test/lib/process/StreamPumper.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -95,13 +95,15 @@ public StreamPumper(InputStream in, OutputStream out) {
 
     /**
      * Implements Thread.run(). Continuously read from {@code in} and write to
-     * {@code out} until {@code in} has reached end of stream. Abort on
-     * interruption. Abort on IOExceptions.
+     * {@code out} until {@code in} has reached end of stream.
+     * Additionally this method also splits the data read from the buffer into lines,
+     * and processes each line using linePumps.
+     * Abort on interruption. Abort on IOExceptions.
      */
     @Override
     public void run() {
-        try (BufferedInputStream is = new BufferedInputStream(in)) {
-            ByteArrayOutputStream lineBos = new ByteArrayOutputStream();
+        try (BufferedInputStream is = new BufferedInputStream(in);
+            ByteArrayOutputStream lineBos = new ByteArrayOutputStream()) {
             byte[] buf = new byte[BUF_SIZE];
             int len = 0;
             int linelen = 0;
@@ -133,6 +135,10 @@ public void run() {
 
                         i++;
                     }
+                    // If no crlf was found, or there was additional data after the last crlf was found, then write the leftover data
+                    // in lineBos. If there is more data to read it will be concatenated with the current data on the next iteration.
+                    // If there is no more data, or no more crlf found, all the remaining data will be processed after the loop, as the
+                    // final line.
                     if (lastcrlf == -1) {
                         lineBos.write(buf, 0, len);
                         linelen += len;
@@ -143,6 +149,12 @@ public void run() {
                 }
             }
 
+            // If there was no terminating crlf the remaining data has been written to lineBos,
+            // but this final line of data now needs to be processed by the linePumper.
+            final String line = lineBos.toString();
+            if (!line.isEmpty()) {
+                linePumps.forEach((lp) -> lp.processLine(line));
+            }
         } catch (IOException e) {
             if (!e.getMessage().equalsIgnoreCase("stream closed")) {
                 e.printStackTrace();