diff --git a/gclc/src/main/java/net/bigeon/gclc/command/CommandParameters.java b/gclc/src/main/java/net/bigeon/gclc/command/CommandParameters.java
index 1a88464..3a83d4f 100644
--- a/gclc/src/main/java/net/bigeon/gclc/command/CommandParameters.java
+++ b/gclc/src/main/java/net/bigeon/gclc/command/CommandParameters.java
@@ -103,7 +103,7 @@ public final class CommandParameters {
      * @param key the key
      * @return if the key was specified */
     public boolean isActive(final String key) {
-        Boolean val = booleanArguments.get(key);
+        final Boolean val = booleanArguments.get(key);
         return val != null && val.booleanValue();
     }
 
@@ -198,9 +198,8 @@ public final class CommandParameters {
      * @param string the key
      * @param value the value */
     public void set(final String string, final boolean value) {
-        if (booleanArguments.containsKey(string)) {
-            booleanArguments.put(string, Boolean.valueOf(value));
-        }
+        booleanArguments.computeIfPresent(string,
+                (final String k, final Boolean v) -> Boolean.valueOf(value));
     }
 
     /** Set a string parameter value.
@@ -208,8 +207,7 @@ public final class CommandParameters {
      * @param string the key
      * @param value the value */
     public void set(final String string, final String value) {
-        if (stringArguments.containsKey(string)) {
-            stringArguments.put(string, value);
-        }
+        stringArguments.computeIfPresent(string,
+                (final String k, final String v) -> value);
     }
 }
diff --git a/gclc/src/main/java/net/bigeon/gclc/command/ParametrizedCommandData.java b/gclc/src/main/java/net/bigeon/gclc/command/ParametrizedCommandData.java
index 9394524..c78a7a7 100644
--- a/gclc/src/main/java/net/bigeon/gclc/command/ParametrizedCommandData.java
+++ b/gclc/src/main/java/net/bigeon/gclc/command/ParametrizedCommandData.java
@@ -149,14 +149,16 @@ public final class ParametrizedCommandData {
      * @param needed if the parameter is needed
      * @throws InvalidParameterException if the new definition is invalid */
     private void checkParam(final String param, final boolean needed) {
-        final Boolean val = stringParams.get(param);
-        if (val != null) {
-            final Boolean need = Boolean.valueOf(needed || val.booleanValue());
-            stringParams.put(param, need);
+        final Boolean val = stringParams.computeIfPresent(param,
+                (final String k, final Boolean v) -> {
+                    final Boolean need = Boolean.valueOf(needed || v.booleanValue());
             params.put(param, need);
-            return;
+                    return need;
+                });
+        if (val == null) {
+            throw new InvalidParameterException(
+                    "Parameter is already defined as boolean"); //$NON-NLS-1$
         }
-        throw new InvalidParameterException("Parameter is already defined as boolean"); //$NON-NLS-1$
     }
 
     /** Retrieve the boolean parameters (aka flags).
diff --git a/gclc/src/main/java/net/bigeon/gclc/utils/ReadingRunnable.java b/gclc/src/main/java/net/bigeon/gclc/utils/ReadingRunnable.java
index 8939e77..8f2a0e9 100644
--- a/gclc/src/main/java/net/bigeon/gclc/utils/ReadingRunnable.java
+++ b/gclc/src/main/java/net/bigeon/gclc/utils/ReadingRunnable.java
@@ -202,9 +202,7 @@ public final class ReadingRunnable implements Runnable {
     public void waitForDelivery(final String message) throws InterruptedException {
         Object mLock;
         synchronized (messageBlockerLock) {
-            if (!messageBlocker.containsKey(message)) {
-                messageBlocker.put(message, new Object());
-            }
+            messageBlocker.computeIfAbsent(message, (final String k) -> new Object());
             mLock = messageBlocker.get(message);
         }
         synchronized (mLock) {