JSR 305 intergration #101

appveyor.yml

@@ -27,7 +27,7 @@ install:
 test_script:
   - ./mvnw.cmd clean install --batch-mode
   - ./mvnw.cmd dependency:copy-dependencies -DincludeScope=test
-  - rm target/dependency/javassist*
+  - rm target/dependency/javassist* target/dependency/jsr305-*
   - echo "Run Agent test"
   - ps: |
       $ttl_jar=Get-ChildItem target\transmittable-thread-local-*.jar -Exclude *-sources.jar | Select-Object -ExpandProperty FullName

pom.xml

@@ -95,6 +95,12 @@
 			<version>3.23.1-GA</version>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>com.google.code.findbugs</groupId>
+			<artifactId>jsr305</artifactId>
+			<version>3.0.2</version>
+			<optional>true</optional>
+		</dependency>
 		<!-- Testing frameworks and related dependencies -->
 		<dependency>
 			<groupId>junit</groupId>

pom4ide.xml

@@ -95,6 +95,12 @@
 			<version>3.23.1-GA</version>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>com.google.code.findbugs</groupId>
+			<artifactId>jsr305</artifactId>
+			<version>3.0.2</version>
+			<optional>true</optional>
+		</dependency>
 		<!-- Testing frameworks and related dependencies -->
 		<dependency>
 			<groupId>junit</groupId>

scripts/common.sh

@@ -117,13 +117,13 @@ mvnCopyDependencies() {
     runCmd "${MVN_CMD[@]}" dependency:copy-dependencies -DincludeScope=test || die "fail to mvn copy-dependencies!"
 
     # remove repackaged and shaded javassist lib
-    rm $dependencies_dir/javassist-*
+    rm "$dependencies_dir"/javassist-* "$dependencies_dir"/jsr305-*
 }
 
 getClasspathOfDependencies() {
     [ -e "$dependencies_dir" ] || mvnCopyDependencies 1>&2
 
-    echo $dependencies_dir/*.jar | tr ' ' :
+    echo "$dependencies_dir"/*.jar | tr ' ' :
 }
 
 getClasspathWithoutTtlJar() {

src/main/java/com/alibaba/ttl/TransmittableThreadLocal.java

 package com.alibaba.ttl;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -145,7 +147,7 @@ public class TransmittableThreadLocal<T> extends InheritableThreadLocal<T> {
     /**
      * Debug only method!
      */
-    static void dump(String title) {
+    static void dump(@Nullable String title) {
         if (title != null && title.length() > 0) {
             System.out.printf("Start TransmittableThreadLocal[%s] Dump...\n", title);
         } else {
@@ -248,6 +250,7 @@ public class TransmittableThreadLocal<T> extends InheritableThreadLocal<T> {
          * @return the captured {@link TransmittableThreadLocal} values
          * @since 2.3.0
          */
+        @Nonnull
         public static Object capture() {
             Map<TransmittableThreadLocal<?>, Object> captured = new HashMap<TransmittableThreadLocal<?>, Object>();
             for (TransmittableThreadLocal<?> threadLocal : holder.get().keySet()) {
@@ -265,7 +268,8 @@ public class TransmittableThreadLocal<T> extends InheritableThreadLocal<T> {
          * @see #capture()
          * @since 2.3.0
          */
-        public static Object replay(Object captured) {
+        @Nonnull
+        public static Object replay(@Nonnull Object captured) {
             @SuppressWarnings("unchecked")
             Map<TransmittableThreadLocal<?>, Object> capturedMap = (Map<TransmittableThreadLocal<?>, Object>) captured;
             Map<TransmittableThreadLocal<?>, Object> backup = new HashMap<TransmittableThreadLocal<?>, Object>();
@@ -301,7 +305,7 @@ public class TransmittableThreadLocal<T> extends InheritableThreadLocal<T> {
          * @param backup the backup {@link TransmittableThreadLocal} values from {@link Transmitter#replay(Object)}
          * @since 2.3.0
          */
-        public static void restore(Object backup) {
+        public static void restore(@Nonnull Object backup) {
             @SuppressWarnings("unchecked")
             Map<TransmittableThreadLocal<?>, Object> backupMap = (Map<TransmittableThreadLocal<?>, Object>) backup;
             // call afterExecute callback
@@ -324,7 +328,7 @@ public class TransmittableThreadLocal<T> extends InheritableThreadLocal<T> {
             setTtlValuesTo(backupMap);
         }
 
-        private static void setTtlValuesTo(Map<TransmittableThreadLocal<?>, Object> ttlValues) {
+        private static void setTtlValuesTo(@Nonnull Map<TransmittableThreadLocal<?>, Object> ttlValues) {
             for (Map.Entry<TransmittableThreadLocal<?>, Object> entry : ttlValues.entrySet()) {
                 @SuppressWarnings("unchecked")
                 TransmittableThreadLocal<Object> threadLocal = (TransmittableThreadLocal<Object>) entry.getKey();
@@ -344,7 +348,7 @@ public class TransmittableThreadLocal<T> extends InheritableThreadLocal<T> {
          * @see #restore(Object)
          * @since 2.3.1
          */
-        public static <R> R runSupplierWithCaptured(Object captured, Supplier<R> bizLogic) {
+        public static <R> R runSupplierWithCaptured(@Nonnull Object captured, Supplier<R> bizLogic) {
             Object backup = replay(captured);
             try {
                 return bizLogic.get();

src/main/java/com/alibaba/ttl/TtlCallable.java

 package com.alibaba.ttl;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -31,7 +33,7 @@ public final class TtlCallable<V> implements Callable<V> {
     private final Callable<V> callable;
     private final boolean releaseTtlValueReferenceAfterCall;
 
-    private TtlCallable(Callable<V> callable, boolean releaseTtlValueReferenceAfterCall) {
+    private TtlCallable(@Nonnull Callable<V> callable, boolean releaseTtlValueReferenceAfterCall) {
         this.capturedRef = new AtomicReference<Object>(capture());
         this.callable = callable;
         this.releaseTtlValueReferenceAfterCall = releaseTtlValueReferenceAfterCall;
@@ -55,6 +57,7 @@ public final class TtlCallable<V> implements Callable<V> {
         }
     }
 
+    @Nonnull
     public Callable<V> getCallable() {
         return callable;
     }
@@ -101,7 +104,8 @@ public final class TtlCallable<V> implements Callable<V> {
      * @param releaseTtlValueReferenceAfterCall release TTL value reference after run, avoid memory leak even if {@link TtlRunnable} is referred.
      * @return Wrapped {@link Callable}
      */
-    public static <T> TtlCallable<T> get(Callable<T> callable, boolean releaseTtlValueReferenceAfterCall) {
+    @Nullable
+    public static <T> TtlCallable<T> get(@Nullable Callable<T> callable, boolean releaseTtlValueReferenceAfterCall) {
         return get(callable, releaseTtlValueReferenceAfterCall, false);
     }
 
@@ -115,7 +119,8 @@ public final class TtlCallable<V> implements Callable<V> {
      * @param idempotent                        is idempotent or not. {@code true} will cover up bugs! <b>DO NOT</b> set, only when you know why.
      * @return Wrapped {@link Callable}
      */
-    public static <T> TtlCallable<T> get(Callable<T> callable, boolean releaseTtlValueReferenceAfterCall, boolean idempotent) {
+    @Nullable
+    public static <T> TtlCallable<T> get(@Nullable Callable<T> callable, boolean releaseTtlValueReferenceAfterCall, boolean idempotent) {
         if (null == callable) {
             return null;
         }
@@ -137,7 +142,8 @@ public final class TtlCallable<V> implements Callable<V> {
      * @param tasks task to be wrapped
      * @return Wrapped {@link Callable}
      */
-    public static <T> List<TtlCallable<T>> gets(Collection<? extends Callable<T>> tasks) {
+    @Nonnull
+    public static <T> List<TtlCallable<T>> gets(@Nullable Collection<? extends Callable<T>> tasks) {
         return gets(tasks, false, false);
     }
 
@@ -148,7 +154,8 @@ public final class TtlCallable<V> implements Callable<V> {
      * @param releaseTtlValueReferenceAfterCall release TTL value reference after run, avoid memory leak even if {@link TtlRunnable} is referred.
      * @return Wrapped {@link Callable}
      */
-    public static <T> List<TtlCallable<T>> gets(Collection<? extends Callable<T>> tasks, boolean releaseTtlValueReferenceAfterCall) {
+    @Nonnull
+    public static <T> List<TtlCallable<T>> gets(@Nullable Collection<? extends Callable<T>> tasks, boolean releaseTtlValueReferenceAfterCall) {
         return gets(tasks, releaseTtlValueReferenceAfterCall, false);
     }
 
@@ -160,7 +167,8 @@ public final class TtlCallable<V> implements Callable<V> {
      * @param idempotent                        is idempotent or not. {@code true} will cover up bugs! <b>DO NOT</b> set, only when you know why.
      * @return Wrapped {@link Callable}
      */
-    public static <T> List<TtlCallable<T>> gets(Collection<? extends Callable<T>> tasks, boolean releaseTtlValueReferenceAfterCall, boolean idempotent) {
+    @Nonnull
+    public static <T> List<TtlCallable<T>> gets(@Nullable Collection<? extends Callable<T>> tasks, boolean releaseTtlValueReferenceAfterCall, boolean idempotent) {
         if (null == tasks) {
             return Collections.emptyList();
         }

src/main/java/com/alibaba/ttl/TtlRunnable.java

 package com.alibaba.ttl;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -28,7 +30,7 @@ public final class TtlRunnable implements Runnable {
     private final Runnable runnable;
     private final boolean releaseTtlValueReferenceAfterRun;
 
-    private TtlRunnable(Runnable runnable, boolean releaseTtlValueReferenceAfterRun) {
+    private TtlRunnable(@Nonnull Runnable runnable, boolean releaseTtlValueReferenceAfterRun) {
         this.capturedRef = new AtomicReference<Object>(capture());
         this.runnable = runnable;
         this.releaseTtlValueReferenceAfterRun = releaseTtlValueReferenceAfterRun;
@@ -55,6 +57,7 @@ public final class TtlRunnable implements Runnable {
     /**
      * return original/unwrapped {@link Runnable}.
      */
+    @Nonnull
     public Runnable getRunnable() {
         return runnable;
     }
@@ -86,7 +89,8 @@ public final class TtlRunnable implements Runnable {
      * @return Wrapped {@link Runnable}
      * @throws IllegalStateException when input is {@link TtlRunnable} already.
      */
-    public static TtlRunnable get(Runnable runnable) {
+    @Nullable
+    public static TtlRunnable get(@Nullable Runnable runnable) {
         return get(runnable, false, false);
     }
 
@@ -98,7 +102,8 @@ public final class TtlRunnable implements Runnable {
      * @return Wrapped {@link Runnable}
      * @throws IllegalStateException when input is {@link TtlRunnable} already.
      */
-    public static TtlRunnable get(Runnable runnable, boolean releaseTtlValueReferenceAfterRun) {
+    @Nullable
+    public static TtlRunnable get(@Nullable Runnable runnable, boolean releaseTtlValueReferenceAfterRun) {
         return get(runnable, releaseTtlValueReferenceAfterRun, false);
     }
 
@@ -113,7 +118,8 @@ public final class TtlRunnable implements Runnable {
      * @return Wrapped {@link Runnable}
      * @throws IllegalStateException when input is {@link TtlRunnable} already and not idempotent.
      */
-    public static TtlRunnable get(Runnable runnable, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
+    @Nullable
+    public static TtlRunnable get(@Nullable Runnable runnable, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
         if (null == runnable) {
             return null;
         }
@@ -136,7 +142,8 @@ public final class TtlRunnable implements Runnable {
      * @return wrapped tasks
      * @throws IllegalStateException when input is {@link TtlRunnable} already.
      */
-    public static List<TtlRunnable> gets(Collection<? extends Runnable> tasks) {
+    @Nonnull
+    public static List<TtlRunnable> gets(@Nullable Collection<? extends Runnable> tasks) {
         return gets(tasks, false, false);
     }
 
@@ -148,7 +155,8 @@ public final class TtlRunnable implements Runnable {
      * @return wrapped tasks
      * @throws IllegalStateException when input is {@link TtlRunnable} already.
      */
-    public static List<TtlRunnable> gets(Collection<? extends Runnable> tasks, boolean releaseTtlValueReferenceAfterRun) {
+    @Nonnull
+    public static List<TtlRunnable> gets(@Nullable Collection<? extends Runnable> tasks, boolean releaseTtlValueReferenceAfterRun) {
         return gets(tasks, releaseTtlValueReferenceAfterRun, false);
     }
 
@@ -163,7 +171,8 @@ public final class TtlRunnable implements Runnable {
      * @return wrapped tasks
      * @throws IllegalStateException when input is {@link TtlRunnable} already and not idempotent.
      */
-    public static List<TtlRunnable> gets(Collection<? extends Runnable> tasks, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
+    @Nonnull
+    public static List<TtlRunnable> gets(@Nullable Collection<? extends Runnable> tasks, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
         if (null == tasks) {
             return Collections.emptyList();
         }

src/main/java/com/alibaba/ttl/TtlTimerTask.java

 package com.alibaba.ttl;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.TimerTask;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -28,7 +30,7 @@ public final class TtlTimerTask extends TimerTask {
     private final TimerTask timerTask;
     private final boolean releaseTtlValueReferenceAfterRun;
 
-    private TtlTimerTask(TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun) {
+    private TtlTimerTask(@Nonnull TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun) {
         this.capturedRef = new AtomicReference<Object>(capture());
         this.timerTask = timerTask;
         this.releaseTtlValueReferenceAfterRun = releaseTtlValueReferenceAfterRun;
@@ -58,6 +60,7 @@ public final class TtlTimerTask extends TimerTask {
         return super.cancel();
     }
 
+    @Nonnull
     public TimerTask getTimerTask() {
         return timerTask;
     }
@@ -70,7 +73,8 @@ public final class TtlTimerTask extends TimerTask {
      * @param timerTask input {@link TimerTask}
      * @return Wrapped {@link TimerTask}
      */
-    public static TtlTimerTask get(TimerTask timerTask) {
+    @Nullable
+    public static TtlTimerTask get(@Nullable TimerTask timerTask) {
         return get(timerTask, false, false);
     }
 
@@ -83,7 +87,8 @@ public final class TtlTimerTask extends TimerTask {
      * @param releaseTtlValueReferenceAfterRun release TTL value reference after run, avoid memory leak even if {@link TtlRunnable} is referred.
      * @return Wrapped {@link TimerTask}
      */
-    public static TtlTimerTask get(TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun) {
+    @Nullable
+    public static TtlTimerTask get(@Nullable TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun) {
         return get(timerTask, releaseTtlValueReferenceAfterRun, false);
     }
 
@@ -97,7 +102,8 @@ public final class TtlTimerTask extends TimerTask {
      * @param idempotent                       is idempotent or not. {@code true} will cover up bugs! <b>DO NOT</b> set, only when you know why.
      * @return Wrapped {@link TimerTask}
      */
-    public static TtlTimerTask get(TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
+    @Nullable
+    public static TtlTimerTask get(@Nullable TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
         if (null == timerTask) {
             return null;
         }

src/main/java/com/alibaba/ttl/threadpool/ExecutorServiceTtlWrapper.java

@@ -4,6 +4,7 @@ import com.alibaba.ttl.TransmittableThreadLocal;
 import com.alibaba.ttl.TtlCallable;
 import com.alibaba.ttl.TtlRunnable;
 
+import javax.annotation.Nonnull;
 import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.*;
@@ -19,7 +20,7 @@ import java.util.concurrent.*;
 class ExecutorServiceTtlWrapper extends ExecutorTtlWrapper implements ExecutorService {
     private final ExecutorService executorService;
 
-    ExecutorServiceTtlWrapper(ExecutorService executorService) {
+    ExecutorServiceTtlWrapper(@Nonnull ExecutorService executorService) {
         super(executorService);
         this.executorService = executorService;
     }
@@ -29,6 +30,7 @@ class ExecutorServiceTtlWrapper extends ExecutorTtlWrapper implements ExecutorSe
         executorService.shutdown();
     }
 
+    @Nonnull
     @Override
     public List<Runnable> shutdownNow() {
         return executorService.shutdownNow();
@@ -45,45 +47,52 @@ class ExecutorServiceTtlWrapper extends ExecutorTtlWrapper implements ExecutorSe
     }
 
     @Override
-    public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
+    public boolean awaitTermination(long timeout, @Nonnull TimeUnit unit) throws InterruptedException {
         return executorService.awaitTermination(timeout, unit);
     }
 
+    @Nonnull
     @Override
-    public <T> Future<T> submit(Callable<T> task) {
+    public <T> Future<T> submit(@Nonnull Callable<T> task) {
         return executorService.submit(TtlCallable.get(task));
     }
 
+    @Nonnull
     @Override
-    public <T> Future<T> submit(Runnable task, T result) {
+    public <T> Future<T> submit(@Nonnull Runnable task, T result) {
         return executorService.submit(TtlRunnable.get(task), result);
     }
 
+    @Nonnull
     @Override
-    public Future<?> submit(Runnable task) {
+    public Future<?> submit(@Nonnull Runnable task) {
         return executorService.submit(TtlRunnable.get(task));
     }
 
+    @Nonnull
     @Override
-    public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {
+    public <T> List<Future<T>> invokeAll(@Nonnull Collection<? extends Callable<T>> tasks) throws InterruptedException {
         return executorService.invokeAll(TtlCallable.gets(tasks));
     }
 
+    @Nonnull
     @Override
-    public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException {
+    public <T> List<Future<T>> invokeAll(@Nonnull Collection<? extends Callable<T>> tasks, long timeout, @Nonnull TimeUnit unit) throws InterruptedException {
         return executorService.invokeAll(TtlCallable.gets(tasks), timeout, unit);
     }
 
+    @Nonnull
     @Override
-    public <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {
+    public <T> T invokeAny(@Nonnull Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {
         return executorService.invokeAny(TtlCallable.gets(tasks));
     }
 
     @Override
-    public <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
+    public <T> T invokeAny(@Nonnull Collection<? extends Callable<T>> tasks, long timeout, @Nonnull TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
         return executorService.invokeAny(TtlCallable.gets(tasks), timeout, unit);
     }
 
+    @Nonnull
     @Override
     public ExecutorService unwrap() {
         return executorService;

src/main/java/com/alibaba/ttl/threadpool/ExecutorTtlWrapper.java

@@ -3,6 +3,7 @@ package com.alibaba.ttl.threadpool;
 import com.alibaba.ttl.TransmittableThreadLocal;
 import com.alibaba.ttl.TtlRunnable;
 
+import javax.annotation.Nonnull;
 import java.util.concurrent.Executor;
 
 /**
@@ -16,15 +17,16 @@ import java.util.concurrent.Executor;
 class ExecutorTtlWrapper implements Executor {
     private final Executor executor;
 
-    ExecutorTtlWrapper(Executor executor) {
+    ExecutorTtlWrapper(@Nonnull Executor executor) {
         this.executor = executor;
     }
 
     @Override
-    public void execute(Runnable command) {
+    public void execute(@Nonnull Runnable command) {
         executor.execute(TtlRunnable.get(command));
     }
 
+    @Nonnull
     public Executor unwrap() {
         return executor;
     }

src/main/java/com/alibaba/ttl/threadpool/ScheduledExecutorServiceTtlWrapper.java

@@ -4,6 +4,7 @@ import com.alibaba.ttl.TransmittableThreadLocal;
 import com.alibaba.ttl.TtlCallable;
 import com.alibaba.ttl.TtlRunnable;
 
+import javax.annotation.Nonnull;
 import java.util.concurrent.*;
 
 /**
@@ -17,32 +18,37 @@ import java.util.concurrent.*;
 class ScheduledExecutorServiceTtlWrapper extends ExecutorServiceTtlWrapper implements ScheduledExecutorService {
     final ScheduledExecutorService scheduledExecutorService;
 
-    public ScheduledExecutorServiceTtlWrapper(ScheduledExecutorService scheduledExecutorService) {
+    public ScheduledExecutorServiceTtlWrapper(@Nonnull ScheduledExecutorService scheduledExecutorService) {
         super(scheduledExecutorService);
         this.scheduledExecutorService = scheduledExecutorService;
     }
 
+    @Nonnull
     @Override
-    public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
+    public ScheduledFuture<?> schedule(@Nonnull Runnable command, long delay, @Nonnull TimeUnit unit) {
         return scheduledExecutorService.schedule(TtlRunnable.get(command), delay, unit);
     }
 
+    @Nonnull
     @Override
-    public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) {
+    public <V> ScheduledFuture<V> schedule(@Nonnull Callable<V> callable, long delay, @Nonnull TimeUnit unit) {
         return scheduledExecutorService.schedule(TtlCallable.get(callable), delay, unit);
     }
 
+    @Nonnull
     @Override
-    public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
+    public ScheduledFuture<?> scheduleAtFixedRate(@Nonnull Runnable command, long initialDelay, long period, @Nonnull TimeUnit unit) {
         return scheduledExecutorService.scheduleAtFixedRate(TtlRunnable.get(command), initialDelay, period, unit);
     }
 
+    @Nonnull
     @Override
-    public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
+    public ScheduledFuture<?> scheduleWithFixedDelay(@Nonnull Runnable command, long initialDelay, long delay, @Nonnull TimeUnit unit) {
         return scheduledExecutorService.scheduleWithFixedDelay(TtlRunnable.get(command), initialDelay, delay, unit);
     }
 
     @Override
+    @Nonnull
     public ScheduledExecutorService unwrap() {
         return scheduledExecutorService;
     }

src/main/java/com/alibaba/ttl/threadpool/TtlExecutors.java

@@ -2,6 +2,7 @@ package com.alibaba.ttl.threadpool;
 
 import com.alibaba.ttl.TransmittableThreadLocal;
 
+import javax.annotation.Nullable;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ScheduledExecutorService;
@@ -25,7 +26,8 @@ public final class TtlExecutors {
      * transmit the {@link TransmittableThreadLocal} from the task submit time of {@link Runnable}
      * to the execution time of {@link Runnable}.
      */
-    public static Executor getTtlExecutor(Executor executor) {
+    @Nullable
+    public static Executor getTtlExecutor(@Nullable Executor executor) {
         if (null == executor || executor instanceof ExecutorTtlWrapper) {
             return executor;
         }
@@ -37,7 +39,8 @@ public final class TtlExecutors {
      * transmit the {@link TransmittableThreadLocal} from the task submit time of {@link Runnable} or {@link java.util.concurrent.Callable}
      * to the execution time of {@link Runnable} or {@link java.util.concurrent.Callable}.
      */
-    public static ExecutorService getTtlExecutorService(ExecutorService executorService) {
+    @Nullable
+    public static ExecutorService getTtlExecutorService(@Nullable ExecutorService executorService) {
         if (executorService == null || executorService instanceof ExecutorServiceTtlWrapper) {
             return executorService;
         }
@@ -49,7 +52,8 @@ public final class TtlExecutors {
      * transmit the {@link TransmittableThreadLocal} from the task submit time of {@link Runnable} or {@link java.util.concurrent.Callable}
      * to the execution time of {@link Runnable} or {@link java.util.concurrent.Callable}.
      */
-    public static ScheduledExecutorService getTtlScheduledExecutorService(ScheduledExecutorService scheduledExecutorService) {
+    @Nullable
+    public static ScheduledExecutorService getTtlScheduledExecutorService(@Nullable ScheduledExecutorService scheduledExecutorService) {
         if (scheduledExecutorService == null || scheduledExecutorService instanceof ScheduledExecutorServiceTtlWrapper) {
             return scheduledExecutorService;
         }
@@ -71,7 +75,7 @@ public final class TtlExecutors {
      * @see #unwrap(Executor)
      * @since 2.8.0
      */
-    public static <T extends Executor> boolean isTtlWrapper(T executor) {
+    public static <T extends Executor> boolean isTtlWrapper(@Nullable T executor) {
         return (executor instanceof ExecutorTtlWrapper);
     }
 
@@ -91,8 +95,9 @@ public final class TtlExecutors {
      * @see #isTtlWrapper(Executor)
      * @since 2.8.0
      */
+    @Nullable
     @SuppressWarnings("unchecked")
-    public static <T extends Executor> T unwrap(T executor) {
+    public static <T extends Executor> T unwrap(@Nullable T executor) {
         if (!isTtlWrapper(executor)) return executor;
 
         return (T) ((ExecutorTtlWrapper) executor).unwrap();

src/main/java/com/alibaba/ttl/threadpool/agent/TtlAgent.java

@@ -7,6 +7,8 @@ import com.alibaba.ttl.threadpool.agent.internal.transformlet.impl.TtlExecutorTr
 import com.alibaba.ttl.threadpool.agent.internal.transformlet.impl.TtlForkJoinTransformlet;
 import com.alibaba.ttl.threadpool.agent.internal.transformlet.impl.TtlTimerTaskTransformlet;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.lang.instrument.ClassFileTransformer;
 import java.lang.instrument.Instrumentation;
 import java.util.ArrayList;
@@ -91,7 +93,7 @@ public final class TtlAgent {
      * @see Logger#STDERR
      * @see Logger#STDOUT
      */
-    public static void premain(String agentArgs, Instrumentation inst) {
+    public static void premain(String agentArgs, @Nonnull Instrumentation inst) {
         final Map<String, String> kvs = splitCommaColonStringToKV(agentArgs);
 
         Logger.setLoggerImplType(getLogImplTypeFromAgentArgs(kvs));
@@ -119,13 +121,13 @@ public final class TtlAgent {
         }
     }
 
-    private static String getLogImplTypeFromAgentArgs(final Map<String, String> kvs) {
+    private static String getLogImplTypeFromAgentArgs(@Nonnull final Map<String, String> kvs) {
         return kvs.get(Logger.TTL_AGENT_LOGGER_KEY);
     }
 
     private static final String TTL_AGENT_ENABLE_TIMER_TASK_KEY = "ttl.agent.enable.timer.task";
 
-    private static boolean enableTimerTask(final Map<String, String> kvs) {
+    private static boolean enableTimerTask(@Nonnull final Map<String, String> kvs) {
         final boolean hasEnableKey = kvs.containsKey(TTL_AGENT_ENABLE_TIMER_TASK_KEY);
         if (!hasEnableKey) return false;
 
@@ -135,7 +137,8 @@ public final class TtlAgent {
     /**
      * Split to {@code json} like String({@code "k1:v1,k2:v2"}) to KV map({@code "k1"->"v1", "k2"->"v2"}).
      */
-    static Map<String, String> splitCommaColonStringToKV(String commaColonString) {
+    @Nonnull
+    static Map<String, String> splitCommaColonStringToKV(@Nullable String commaColonString) {
         Map<String, String> ret = new HashMap<String, String>();
         if (commaColonString == null || commaColonString.trim().length() == 0) return ret;
 

src/main/java/com/alibaba/ttl/threadpool/agent/TtlTransformer.java

@@ -3,6 +3,8 @@ package com.alibaba.ttl.threadpool.agent;
 import com.alibaba.ttl.threadpool.agent.internal.logging.Logger;
 import com.alibaba.ttl.threadpool.agent.internal.transformlet.JavassistTransformlet;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.lang.instrument.ClassFileTransformer;
 import java.security.ProtectionDomain;
 import java.util.ArrayList;
@@ -34,7 +36,7 @@ public class TtlTransformer implements ClassFileTransformer {
     }
 
     @Override
-    public final byte[] transform(final ClassLoader loader, final String classFile, final Class<?> classBeingRedefined,
+    public final byte[] transform(@Nonnull final ClassLoader loader, @Nullable final String classFile, final Class<?> classBeingRedefined,
                                   final ProtectionDomain protectionDomain, final byte[] classFileBuffer) {
         try {
             // Lambda has no class file, no need to transform, just return.

src/test/java/com/alibaba/demo/distributed_tracer/refcount/DistributedTracerUseDemo.kt

@@ -43,11 +43,9 @@ private fun rpcInvokeIn() {
     decreaseSpanIdRefCount()
 }
 
-private val executorService = TtlExecutors.getTtlExecutorService(
-        Executors.newFixedThreadPool(1) { r: Runnable ->
-            Thread(r, "Executors").apply { isDaemon = true }
-        }
-)
+private val executorService = Executors.newFixedThreadPool(1) { r: Runnable ->
+    Thread(r, "Executors").apply { isDaemon = true }
+}.let { TtlExecutors.getTtlExecutorService(it) }!!
 
 private fun syncMethod() {
     // async call by TTL Executor, Test OK!

src/test/java/com/alibaba/demo/distributed_tracer/weakref/DistributedTracerUseDemo_WeakReferenceInsteadOfRefCounter.kt

@@ -17,7 +17,7 @@ private val executorService: ExecutorService = Executors.newFixedThreadPool(1) {
     // ensure threads in pool is pre-created.
     expandThreadPool(it)
     TtlExecutors.getTtlExecutorService(it)
-}
+}!!
 
 /**
  * DistributedTracer(DT) use demo.

src/test/java/com/alibaba/ttl/TtlCallableTest.kt

@@ -94,7 +94,7 @@ class TtlCallableTest {
         val ttlInstances = createParentTtlInstances()
 
         val call = Call("1", ttlInstances)
-        val ttlCallable = TtlCallable.get(call, true)
+        val ttlCallable = TtlCallable.get(call, true)!!
         assertSame(call, ttlCallable.callable)
 
         assertEquals("ok", executorService.submit(ttlCallable).get())

src/test/java/com/alibaba/ttl/TtlRunnableTest.kt

@@ -24,7 +24,7 @@ class TtlRunnableTest {
         val ttlInstances = createParentTtlInstances()
 
         val task = Task("1", ttlInstances)
-        val ttlRunnable = TtlRunnable.get(task)
+        val ttlRunnable = TtlRunnable.get(task)!!
 
         // create after new Task, won't see parent value in in task!
         createParentTtlInstancesAfterCreateChild(ttlInstances)
@@ -204,7 +204,7 @@ class TtlRunnableTest {
     @Test
     fun test_get_same() {
         val task = Task("1")
-        val ttlRunnable = TtlRunnable.get(task)
+        val ttlRunnable = TtlRunnable.get(task)!!
         assertSame(task, ttlRunnable.runnable)
     }
 

src/test/java/com/alibaba/ttl/threadpool/ScheduledExecutorServiceTtlWrapperTest.kt

@@ -235,7 +235,7 @@ class ScheduledExecutorServiceTtlWrapperTest {
             it.setKeepAliveTime(10, TimeUnit.SECONDS)
             expandThreadPool(it)
             TtlExecutors.getTtlScheduledExecutorService(it)
-        }
+        }!!
 
         @AfterClass
         @Suppress("unused")