diff --git a/src/main/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapter.java b/src/main/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapter.java
index cfabdeba8..7a27275fb 100644
--- a/src/main/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapter.java
+++ b/src/main/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapter.java
@@ -364,10 +364,11 @@ public abstract class DefaultCompilerAdapter
                                            ? "1.7 in JDK 1.7"
                                            : "1.8 in JDK 1.8"),
                                         cmd, t, s);
-            } else if (assumeJava17() && (t.equals("1.5") || t.equals("1.6"))) {
+            } else if (assumeJava17() && (t.equals("1.5") || t.equals("1.6") || t.equals("5") || t.equals("6"))) {
                 setImplicitSourceSwitch("1.7 in JDK 1.7", cmd, t, t);
             } else if (assumeJava18() &&
-                       (t.equals("1.5") || t.equals("1.6") || t.equals("1.7"))) {
+                       (t.equals("1.5") || t.equals("1.6") || t.equals("1.7")
+                        || t.equals("5") || t.equals("6") || t.equals("7"))) {
                 setImplicitSourceSwitch("1.8 in JDK 1.8", cmd, t, t);
             }
         }
diff --git a/src/tests/junit/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapterTest.java b/src/tests/junit/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapterTest.java
index 48075df45..c2cec6e66 100644
--- a/src/tests/junit/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapterTest.java
+++ b/src/tests/junit/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapterTest.java
@@ -99,14 +99,12 @@ public class DefaultCompilerAdapterTest extends TestCase {
         testSource("1.6", "javac1.7",
                    "If you specify -target 1.6 you now must also specify"
                    + " -source 1.6", "1.6");
-        /* FIXME - should be adapted as well
         testSource("5", "javac1.7",
                    "If you specify -target 5 you now must also specify"
                    + " -source 5", "5");
         testSource("6", "javac1.7",
                    "If you specify -target 6 you now must also specify"
                    + " -source 6", "6");
-        */
         testSource(null, "javac1.7", "", "1.7");
         testSource(null, "javac1.7", "", "7");
     }
@@ -122,7 +120,6 @@ public class DefaultCompilerAdapterTest extends TestCase {
         testSource("1.7", "javac1.8",
                    "If you specify -target 1.7 you now must also specify"
                    + " -source 1.7", "1.7");
-        /* FIXME - should be adapted as well
         testSource("5", "javac1.8",
                    "If you specify -target 5 you now must also specify"
                    + " -source 5", "5");
@@ -132,7 +129,6 @@ public class DefaultCompilerAdapterTest extends TestCase {
         testSource("7", "javac1.8",
                    "If you specify -target 7 you now must also specify"
                    + " -source 7", "7");
-        */
         testSource(null, "javac1.8", "", "1.8");
         testSource(null, "javac1.8", "", "8");
     }