diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a6bf328f..f8ec63c50 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,9 +11,10 @@ Breaking API changes:
     * See [#768](https://github.com/eclipse-lsp4j/lsp4j/issues/768) for detailed discussion.
   * The name field in WorkspaceFolder is no longer optional according to the specification.
     * See [#741](https://github.com/eclipse-lsp4j/lsp4j/issues/741) for detailed discussion.
-  * The LSP4J generator when applied to `@JsonRpcData` annotated classes generates a dependency on package `org.eclipse.lsp4j.jsonrpc.util` in the `org.eclipse.lsp4j.jsonrpc` bundle to provide an implementation of `ToStringBuilder`.
-    * This removes the implied requirement in LSP4J 0.21.0 that there is a class called `ToStringBuilder` in a sub-package called `util`.
-    * This also removes the duplicated class `ToStringBuilder` in packages `org.eclipse.lsp4j.debug.util` and `org.eclipse.lsp4j.util`.
+  * The LSP4J generator when applied to `@JsonRpcData` annotated classes generates a dependency on package `org.eclipse.lsp4j.jsonrpc.util` in the `org.eclipse.lsp4j.jsonrpc` bundle.
+    * This removes the implied requirement in LSP4J 0.21.0 that there are classes called `ToStringBuilder` and `Preconditions` in a sub-package called `util`;
+      instead, the generator now uses classes `ToStringBuilder` and `Preconditions` in package `org.eclipse.lsp4j.jsonrpc.util`.
+    * Duplicate classes `ToStringBuilder` and `Preconditions` have been removed from `org.eclipse.lsp4j.util` and `org.eclipse.lsp4j.debug.util` packages.
     * See [#742](https://github.com/eclipse-lsp4j/lsp4j/issues/742) for detailed discussion.
 
 Nightly japicmp report: <https://download.eclipse.org/lsp4j/builds/main/japicmp-report/>
diff --git a/org.eclipse.lsp4j.debug/src/main/java/org/eclipse/lsp4j/debug/util/Preconditions.java b/org.eclipse.lsp4j.debug/src/main/java/org/eclipse/lsp4j/debug/util/Preconditions.java
deleted file mode 100644
index 6892a6469..000000000
--- a/org.eclipse.lsp4j.debug/src/main/java/org/eclipse/lsp4j/debug/util/Preconditions.java
+++ /dev/null
@@ -1,34 +0,0 @@
-/******************************************************************************
- * Copyright (c) 2019 TypeFox and others.
- * 
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-2.0,
- * or the Eclipse Distribution License v. 1.0 which is available at
- * http://www.eclipse.org/org/documents/edl-v10.php.
- * 
- * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
- ******************************************************************************/
-package org.eclipse.lsp4j.debug.util;
-
-/**
- * Utilities for checking method and constructor arguments.
- */
-public final class Preconditions {
-	
-	private Preconditions() {}
-	
-	private static boolean nullChecks = true;
-	
-	public static void enableNullChecks(boolean enable) {
-		Preconditions.nullChecks = enable;
-	}
-	
-	public static <T> T checkNotNull(T object, String propertyName) {
-		if (nullChecks && object == null) {
-			throw new IllegalArgumentException("Property must not be null: " + propertyName);
-		}
-		return object;
-	}
-
-}
diff --git a/org.eclipse.lsp4j.generator/src/main/java/org/eclipse/lsp4j/generator/JsonRpcDataProcessor.xtend b/org.eclipse.lsp4j.generator/src/main/java/org/eclipse/lsp4j/generator/JsonRpcDataProcessor.xtend
index 19e32d424..fd226bbb6 100644
--- a/org.eclipse.lsp4j.generator/src/main/java/org/eclipse/lsp4j/generator/JsonRpcDataProcessor.xtend
+++ b/org.eclipse.lsp4j.generator/src/main/java/org/eclipse/lsp4j/generator/JsonRpcDataProcessor.xtend
@@ -172,10 +172,7 @@ class JsonRpcDataProcessor extends AbstractClassProcessor {
 	}
 	
 	private def getPreconditionsUtil(Type type, extension TransformationContext context) {
-		if (type.qualifiedName.startsWith('org.eclipse.lsp4j.debug'))
-			newTypeReference('org.eclipse.lsp4j.debug.util.Preconditions')
-		else
-			newTypeReference('org.eclipse.lsp4j.util.Preconditions')
+		newTypeReference('org.eclipse.lsp4j.jsonrpc.util.Preconditions')
 	}
 
 }
diff --git a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Preconditions.java b/org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/util/Preconditions.java
similarity index 96%
rename from org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Preconditions.java
rename to org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/util/Preconditions.java
index 2319b7ddb..c9f5d3616 100644
--- a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Preconditions.java
+++ b/org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/util/Preconditions.java
@@ -9,7 +9,7 @@
  * 
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  ******************************************************************************/
-package org.eclipse.lsp4j.util;
+package org.eclipse.lsp4j.jsonrpc.util;
 
 /**
  * Utilities for checking method and constructor arguments.
diff --git a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend
index 4a270611d..4ceed3727 100644
--- a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend
+++ b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend
@@ -34,8 +34,8 @@ import org.eclipse.lsp4j.jsonrpc.messages.Either
 import org.eclipse.lsp4j.jsonrpc.messages.Either3
 import org.eclipse.lsp4j.jsonrpc.messages.ResponseErrorCode
 import org.eclipse.lsp4j.jsonrpc.messages.Tuple
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions
 import org.eclipse.lsp4j.jsonrpc.validation.NonNull
-import org.eclipse.lsp4j.util.Preconditions
 
 @JsonRpcData
 class DynamicRegistrationCapabilities {
diff --git a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/DocumentSymbols.java b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/DocumentSymbols.java
index 0763b028d..30b16397d 100644
--- a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/DocumentSymbols.java
+++ b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/DocumentSymbols.java
@@ -16,6 +16,7 @@
 import java.util.Queue;
 
 import org.eclipse.lsp4j.DocumentSymbol;
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions;
 
 /**
  * Utilities for {@link DocumentSymbol document symbols}.
diff --git a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Positions.java b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Positions.java
index a4affc7f5..0623fab26 100644
--- a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Positions.java
+++ b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Positions.java
@@ -12,6 +12,7 @@
 package org.eclipse.lsp4j.util;
 
 import org.eclipse.lsp4j.Position;
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions;
 
 /**
  * Utilities for the {@link Position}.
diff --git a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Ranges.java b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Ranges.java
index ebd4e6987..246d72f88 100644
--- a/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Ranges.java
+++ b/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Ranges.java
@@ -13,6 +13,7 @@
 
 import org.eclipse.lsp4j.Position;
 import org.eclipse.lsp4j.Range;
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions;
 
 /**
  * Utility class for {@link Range}.