diff --git a/README.md b/README.md
index 98d077d..7f1acdf 100644
--- a/README.md
+++ b/README.md
@@ -8,5 +8,6 @@ make a native logging service provider implementation of the [ELF4J](https://git
 Java) SPI. See [elf4j-impl](https://github.com/elf4j/elf4j-impl) for descriptions.
 
 While directly implementing the [ELF4J](https://github.com/elf4j/elf4j) API, this is also a stand-alone Java logging
-engine. It is designed to be adaptable to service other logging APIs, for example, as
-a [logging engine for SLF4J](https://github.com/elf4j/slf4j-elf4j).
\ No newline at end of file
+engine. It is designed to be adaptable to service other logging APIs, for example, as a logging engine
+for [SLF4J](https://github.com/elf4j/slf4j-elf4j) or Java Platform Logging
+API ([JPL](https://github.com/elf4j/jpl-elf4j)) (System.Logger).
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index ed575c6..eacff6b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
 
     <groupId>io.github.elf4j</groupId>
     <artifactId>elf4j-impl-core</artifactId>
-    <version>0.6.4</version>
+    <version>0.7.0</version>
     <packaging>jar</packaging>
     <name>elf4j-impl-core</name>
     <description>Native logging service provider implementation of ELF4J (Easy Logging Facade For Java)
@@ -68,7 +68,7 @@
         <dependency>
             <groupId>io.github.elf4j</groupId>
             <artifactId>elf4j</artifactId>
-            <version>2.0.6</version>
+            <version>2.1.0</version>
         </dependency>
         <dependency>
             <groupId>com.google.code.gson</groupId>
diff --git a/src/main/java/elf4j/impl/core/NativeLogger.java b/src/main/java/elf4j/impl/core/NativeLogger.java
index 48bab69..e59f389 100644
--- a/src/main/java/elf4j/impl/core/NativeLogger.java
+++ b/src/main/java/elf4j/impl/core/NativeLogger.java
@@ -37,20 +37,20 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Function;
-import java.util.stream.Collectors;
+
+import static java.util.stream.Collectors.toMap;
 
 /**
  * Instances of this class are thread-safe, and can be used as class, instance, or local variables. It is recommended,
- * however, to use class variables for instances that are returned by the static factory method
- * {@link Logger#instance()}, as those instances are more expensive to create. Other instances returned by the
- * fluent-style factory methods, such as {@link Logger#atError()}, are inexpensive to create and can be used (and
- * discarded) in-line or as convenient.
+ * however, to use class variables for instances returned by the static factory method {@link Logger#instance()}, as
+ * those instances are more expensive to create. Other instances returned by the fluent-style factory methods, such as
+ * {@link Logger#atLevel}, are inexpensive to create and can be used (and discarded) in-line or as convenient.
  */
 @ThreadSafe
 @Value
 public class NativeLogger implements Logger {
     private static final Map<Level, Map<String, NativeLogger>> NATIVE_LOGGERS =
-            EnumSet.allOf(Level.class).stream().collect(Collectors.toMap(Function.identity(), l -> new HashMap<>()));
+            EnumSet.allOf(Level.class).stream().collect(toMap(Function.identity(), l -> new HashMap<>()));
 
     /**
      * Name of this logger's "owner class" - the logging service client class that first requested for this logger
@@ -82,33 +82,9 @@ public NativeLogger(@NonNull String ownerClassName, @NonNull Level level, @NonNu
     }
 
     @Override
-    public NativeLogger atDebug() {
-        return atLevel(Level.DEBUG);
-    }
-
-    @Override
-    public NativeLogger atError() {
-        return atLevel(Level.ERROR);
-    }
-
-    @Override
-    public NativeLogger atInfo() {
-        return atLevel(Level.INFO);
-    }
-
-    @Override
-    public NativeLogger atTrace() {
-        return atLevel(Level.TRACE);
-    }
-
-    @Override
-    public NativeLogger atWarn() {
-        return atLevel(Level.WARN);
-    }
-
-    @Override
-    public @NonNull Level getLevel() {
-        return this.level;
+    public NativeLogger atLevel(Level level) {
+        return this.level == level ? this : NATIVE_LOGGERS.get(level)
+                .computeIfAbsent(this.ownerClassName, k -> new NativeLogger(k, level, this.logService));
     }
 
     @Override
@@ -141,16 +117,6 @@ public void log(Throwable t, String message, Object... args) {
         this.service(t, message, args);
     }
 
-    /**
-     * @param level of the returned logger instance
-     * @return logger instance of the same owner class name, with the specified level
-     */
-    public NativeLogger atLevel(Level level) {
-        return this.level == level ? this : NATIVE_LOGGERS.get(level)
-                .computeIfAbsent(this.ownerClassName,
-                        k -> new NativeLogger(this.ownerClassName, level, this.logService));
-    }
-
     private void service(Throwable exception, Object message, Object[] args) {
         this.logService.log(this, NativeLogger.class, exception, message, args);
     }
diff --git a/src/test/java/elf4j/impl/core/NativeLoggerTest.java b/src/test/java/elf4j/impl/core/NativeLoggerTest.java
index 0cec597..41ed046 100644
--- a/src/test/java/elf4j/impl/core/NativeLoggerTest.java
+++ b/src/test/java/elf4j/impl/core/NativeLoggerTest.java
@@ -57,8 +57,8 @@ void init() {
     class atLevels {
         @Test
         void instanceForDifferentLevel() {
-            NativeLogger info = nativeLogger.atInfo();
-            NativeLogger warn = info.atWarn();
+            NativeLogger info = (NativeLogger) nativeLogger.atInfo();
+            NativeLogger warn = (NativeLogger) info.atWarn();
 
             assertNotSame(warn, info);
             assertEquals(info.getOwnerClassName(), warn.getOwnerClassName());
@@ -67,11 +67,11 @@ void instanceForDifferentLevel() {
 
         @Test
         void instanceForSameLevel() {
-            NativeLogger trace = nativeLogger.atTrace();
-            NativeLogger debug = nativeLogger.atDebug();
-            NativeLogger info = nativeLogger.atInfo();
-            NativeLogger warn = nativeLogger.atWarn();
-            NativeLogger error = nativeLogger.atError();
+            NativeLogger trace = (NativeLogger) nativeLogger.atTrace();
+            NativeLogger debug = (NativeLogger) nativeLogger.atDebug();
+            NativeLogger info = (NativeLogger) nativeLogger.atInfo();
+            NativeLogger warn = (NativeLogger) nativeLogger.atWarn();
+            NativeLogger error = (NativeLogger) nativeLogger.atError();
 
             assertSame(trace, trace.atTrace());
             assertSame(debug, debug.atDebug());