8342936: Enhance java.io.IO with parameter-less println() and readln()

src/jdk.internal.le/share/classes/jdk/internal/org/jline/JdkConsoleProviderImpl.java

@@ -231,12 +231,7 @@ public String readln(String prompt) {
 
         @Override
         public String readln() {
-            try {
-                initJLineIfNeeded();
-                return jline.readLine();
-            } catch (EndOfFileException eofe) {
-                return null;
-            }
+            return readLine();
         }
 
         @Override
@@ -257,7 +252,12 @@ public String readLine(Locale locale, String format, Object ... args) {
 
         @Override
         public String readLine() {
-            return readLine(Locale.getDefault(Locale.Category.FORMAT), "");
+            try {
+                initJLineIfNeeded();
+                return jline.readLine();
+            } catch (EndOfFileException eofe) {
+                return null;
+            }
         }
 
         @Override

src/jdk.jshell/share/classes/jdk/jshell/execution/impl/ConsoleImpl.java

@@ -240,15 +240,7 @@ public String readln(String prompt) {
          */
         @Override
         public String readln() {
-            try {
-                return sendAndReceive(() -> {
-                    remoteInput.write(Task.READ_LINE_NO_PROMPT.ordinal());
-                    char[] line = readChars();
-                    return new String(line);
-                });
-            } catch (IOException ex) {
-                throw new IOError(ex);
-            }
+            return readLine();
         }
 
         /**
@@ -287,7 +279,15 @@ public String readLine(Locale locale, String format, Object... args) {
          */
         @Override
         public String readLine() {
-            return readLine(Locale.getDefault(Locale.Category.FORMAT), "");
+            try {
+                return sendAndReceive(() -> {
+                    remoteInput.write(Task.READ_LINE_NO_PROMPT.ordinal());
+                    char[] line = readChars();
+                    return new String(line);
+                });
+            } catch (IOException ex) {
+                throw new IOError(ex);
+            }
         }
 
         /**

test/langtools/jdk/jshell/ConsoleTest.java

@@ -25,6 +25,7 @@
  * @test
  * @bug 8298425
  * @summary Verify behavior of System.console()
+ * @enablePreview
  * @build KullaTesting TestingInputStream
  * @run testng ConsoleTest
  */
@@ -67,6 +68,13 @@ public String readLine(String prompt) throws IOError {
             }
         };
         assertEval("System.console().readLine(\"expected\")", "\"AB\"");
+        console = new ThrowingJShellConsole() {
+            @Override
+            public String readLine() throws IOError {
+                return "AB";
+            }
+        };
+        assertEval("System.console().readLine()", "\"AB\"");
         console = new ThrowingJShellConsole() {
             @Override
             public char[] readPassword(String prompt) throws IOError {
@@ -210,6 +218,10 @@ public String readLine(String prompt) throws IOError {
                 return console.readLine(prompt);
             }
             @Override
+            public String readLine() throws IOError {
+                return console.readLine();
+            }
+            @Override
             public char[] readPassword(String prompt) throws IOError {
                 return console.readPassword(prompt);
             }
@@ -240,6 +252,10 @@ public String readLine(String prompt) throws IOError {
             throw new IllegalStateException("Not expected!");
         }
         @Override
+        public String readLine() throws IOError {
+            throw new IllegalStateException("Not expected!");
+        }
+        @Override
         public char[] readPassword(String prompt) throws IOError {
             throw new IllegalStateException("Not expected!");
         }