diff --git a/src/java/org/lwjgl/opengl/AMDDebugOutputCallback.java b/src/java/org/lwjgl/opengl/AMDDebugOutputCallback.java
index 4fcaa653..6cf51fc3 100644
--- a/src/java/org/lwjgl/opengl/AMDDebugOutputCallback.java
+++ b/src/java/org/lwjgl/opengl/AMDDebugOutputCallback.java
@@ -110,7 +110,7 @@ public final class AMDDebugOutputCallback extends PointerWrapperAbstract {
 						description = "OTHER";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(category) + ")";
+						description = printUnknownToken(category);
 				}
 				System.err.println("\tCategory: " + description);
 
@@ -125,12 +125,16 @@ public final class AMDDebugOutputCallback extends PointerWrapperAbstract {
 						description = "LOW";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(category) + ")";
+						description = printUnknownToken(severity);
 				}
 				System.err.println("\tSeverity: " + description);
 
 				System.err.println("\tMessage: " + message);
 			}
+
+			private String printUnknownToken(final int token) {
+				return "Unknown (0x" + Integer.toHexString(token).toUpperCase() + ")";
+			}
 		});
 	}
 
diff --git a/src/java/org/lwjgl/opengl/ARBDebugOutputCallback.java b/src/java/org/lwjgl/opengl/ARBDebugOutputCallback.java
index e1b02dd5..3cbd3dc9 100644
--- a/src/java/org/lwjgl/opengl/ARBDebugOutputCallback.java
+++ b/src/java/org/lwjgl/opengl/ARBDebugOutputCallback.java
@@ -113,7 +113,7 @@ public final class ARBDebugOutputCallback extends PointerWrapperAbstract {
 						description = "OTHER";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(source) + ")";
+						description = printUnknownToken(source);
 				}
 				System.err.println("\tSource: " + description);
 
@@ -137,7 +137,7 @@ public final class ARBDebugOutputCallback extends PointerWrapperAbstract {
 						description = "OTHER";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(source) + ")";
+						description = printUnknownToken(type);
 				}
 				System.err.println("\tType: " + description);
 
@@ -152,12 +152,16 @@ public final class ARBDebugOutputCallback extends PointerWrapperAbstract {
 						description = "LOW";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(source) + ")";
+						description = printUnknownToken(severity);
 				}
 				System.err.println("\tSeverity: " + description);
 
 				System.err.println("\tMessage: " + message);
 			}
+
+			private  String printUnknownToken(final int token) {
+				return "Unknown (0x" + Integer.toHexString(token).toUpperCase() + ")";
+			}
 		});
 	}
 
diff --git a/src/java/org/lwjgl/opengl/KHRDebugCallback.java b/src/java/org/lwjgl/opengl/KHRDebugCallback.java
index ac10d29a..22f55c67 100644
--- a/src/java/org/lwjgl/opengl/KHRDebugCallback.java
+++ b/src/java/org/lwjgl/opengl/KHRDebugCallback.java
@@ -115,7 +115,7 @@ public final class KHRDebugCallback extends PointerWrapperAbstract {
 						description = "OTHER";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(source) + ")";
+						description = printUnknownToken(source);
 				}
 				System.err.println("\tSource: " + description);
 
@@ -142,7 +142,7 @@ public final class KHRDebugCallback extends PointerWrapperAbstract {
 						description = "MARKER";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(source) + ")";
+						description = printUnknownToken(type);
 				}
 				System.err.println("\tType: " + description);
 
@@ -160,12 +160,16 @@ public final class KHRDebugCallback extends PointerWrapperAbstract {
 						description = "NOTIFICATION";
 						break;
 					default:
-						description = "Unknown (" + Integer.toHexString(source) + ")";
+						description = printUnknownToken(severity);
 				}
 				System.err.println("\tSeverity: " + description);
 
 				System.err.println("\tMessage: " + message);
 			}
+
+			private String printUnknownToken(final int token) {
+				return "Unknown (0x" + Integer.toHexString(token).toUpperCase() + ")";
+			}
 		});
 	}