diff --git a/java/ql/src/Likely Bugs/Concurrency/NonSynchronizedOverride.ql b/java/ql/src/Likely Bugs/Concurrency/NonSynchronizedOverride.ql
index ffbe8f34429..eca0dc5f041 100644
--- a/java/ql/src/Likely Bugs/Concurrency/NonSynchronizedOverride.ql	
+++ b/java/ql/src/Likely Bugs/Concurrency/NonSynchronizedOverride.ql	
@@ -3,7 +3,7 @@
  * @description If a synchronized method is overridden in a subclass, and the overriding method is
  *              not synchronized, the thread-safety of the subclass may be broken.
  * @kind problem
- * @problem.severity error
+ * @problem.severity warning
  * @precision very-high
  * @id java/non-sync-override
  * @tags reliability
diff --git a/java/ql/src/Likely Bugs/Resource Leaks/CloseReader.ql b/java/ql/src/Likely Bugs/Resource Leaks/CloseReader.ql
index 5da821a7626..1fd9bddc7bf 100644
--- a/java/ql/src/Likely Bugs/Resource Leaks/CloseReader.ql	
+++ b/java/ql/src/Likely Bugs/Resource Leaks/CloseReader.ql	
@@ -3,7 +3,7 @@
  * @description A resource that is opened for reading but not closed may cause a resource
  *              leak.
  * @kind problem
- * @problem.severity error
+ * @problem.severity warning
  * @precision high
  * @id java/input-resource-leak
  * @tags efficiency
diff --git a/java/ql/src/Likely Bugs/Resource Leaks/CloseSql.ql b/java/ql/src/Likely Bugs/Resource Leaks/CloseSql.ql
index d2681cbb6d1..a2803d7525e 100644
--- a/java/ql/src/Likely Bugs/Resource Leaks/CloseSql.ql	
+++ b/java/ql/src/Likely Bugs/Resource Leaks/CloseSql.ql	
@@ -2,7 +2,7 @@
  * @name Potential database resource leak
  * @description A database resource that is opened but not closed may cause a resource leak.
  * @kind problem
- * @problem.severity error
+ * @problem.severity warning
  * @precision high
  * @id java/database-resource-leak
  * @tags correctness
diff --git a/java/ql/src/Likely Bugs/Resource Leaks/CloseWriter.ql b/java/ql/src/Likely Bugs/Resource Leaks/CloseWriter.ql
index f0ce36cc821..f854c6c7ab6 100644
--- a/java/ql/src/Likely Bugs/Resource Leaks/CloseWriter.ql	
+++ b/java/ql/src/Likely Bugs/Resource Leaks/CloseWriter.ql	
@@ -3,7 +3,7 @@
  * @description A resource that is opened for writing but not closed may cause a resource
  *              leak.
  * @kind problem
- * @problem.severity error
+ * @problem.severity warning
  * @precision high
  * @id java/output-resource-leak
  * @tags efficiency