Fix nullability problems

Author: felixbarny

apm-agent-api/src/main/java/co/elastic/apm/api/ElasticApm.java

@@ -86,9 +86,6 @@ public static ElasticApm get() {
      * @param tracer The tracer implementation to register.
      */
     void register(Tracer tracer) {
-        if (tracer == null) {
-            INSTANCE.tracer = NoopTracer.INSTANCE;
-        }
         INSTANCE.tracer = tracer;
     }
 

apm-agent-core/src/main/java/co/elastic/apm/impl/ElasticApmTracer.java

@@ -139,7 +139,7 @@ public static ElasticApmTracer get() {
      */
     public static void unregister() {
         synchronized (ElasticApmTracer.class) {
-            instance = null;
+            instance = ElasticApmTracer.builder().build().register();
             TracerRegisterer.unregister();
         }
     }
@@ -153,7 +153,6 @@ public ElasticApmTracer register() {
         return this;
     }
 
-    @Nonnull
     @Override
     public Transaction startTransaction() {
         Transaction transaction;
@@ -176,14 +175,13 @@ public Span currentSpan() {
         return currentSpan.get();
     }
 
-    @Nonnull
     @Override
     public Span startSpan() {
         Transaction transaction = currentTransaction();
         final Span span;
         // makes sure that the active setting is consistent during a transaction
         // even when setting active=false mid-transaction
-        if (isNoop(transaction)) {
+        if (isNoop(transaction) || transaction == null) {
             span = noopSpan;
         } else {
             span = createRealSpan(transaction);

apm-agent-core/src/main/java/co/elastic/apm/impl/payload/ProcessFactory.java

@@ -7,9 +7,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -161,7 +161,7 @@ public static ProcessFactory make() {
         @Override
         public ProcessInfo getProcessInformation() {
             ProcessHandle processHandle = (ProcessHandle) this.processHandle;
-            final ProcessInfo process = new ProcessInfo(processHandle.info().command().orElse(null));
+            final ProcessInfo process = new ProcessInfo(processHandle.info().command().orElse("unknown"));
             process.withPid(processHandle.pid());
             process.withPpid(processHandle.parent()
                 .map(new Function<ProcessHandle, Long>() {

apm-agent-core/src/main/java/co/elastic/apm/impl/payload/ProcessInfo.java

@@ -87,7 +87,7 @@ public Long getPpid() {
     /**
      * Parent process ID of the service
      */
-    public ProcessInfo withPpid(Long ppid) {
+    public ProcessInfo withPpid(@Nullable Long ppid) {
         this.ppid = ppid;
         return this;
     }
@@ -108,8 +108,10 @@ public List<String> getArgv() {
     /**
      * Command line arguments used to start this process
      */
-    public ProcessInfo withArgv(List<String> argv) {
-        this.argv = argv;
+    public ProcessInfo withArgv(@Nullable List<String> argv) {
+        if (argv != null) {
+            this.argv.addAll(argv);
+        }
         return this;
     }
 

apm-agent-core/src/main/java/co/elastic/apm/matcher/WildcardMatcher.java

@@ -149,7 +149,7 @@ public static boolean anyMatch(Collection<WildcardMatcher> matchers, String s) {
      * @return {@code true}, if any of the matchers match the provided partitioned string
      * @see #matches(String, String)
      */
-    public static boolean anyMatch(Collection<WildcardMatcher> matchers, @Nullable String firstPart, String secondPart) {
+    public static boolean anyMatch(Collection<WildcardMatcher> matchers, String firstPart, @Nullable String secondPart) {
         for (WildcardMatcher matcher : matchers) {
             if (matcher.matches(firstPart, secondPart)) {
                 return true;

apm-agent-core/src/main/java/co/elastic/apm/objectpool/impl/AbstractObjectPool.java

@@ -49,7 +49,7 @@ public T createInstance() {
     @Override
     public void fillFromOtherPool(ObjectPool<T> otherPool, int maxElements) {
         for (int i = 0; i < maxElements; i++) {
-            T obj = createInstance();
+            T obj = tryCreateInstance();
             if (obj == null) {
                 return;
             }

apm-agent-core/src/main/java/co/elastic/apm/report/ApmServerHttpPayloadSender.java

@@ -7,9 +7,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -35,10 +35,11 @@
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
+import java.util.Objects;
 
 public class ApmServerHttpPayloadSender implements PayloadSender {
     private static final Logger logger = LoggerFactory.getLogger(ApmServerHttpPayloadSender.class);
-    private static final MediaType MEDIA_TYPE_JSON = MediaType.parse("application/json");
+    private static final MediaType MEDIA_TYPE_JSON = Objects.requireNonNull(MediaType.parse("application/json"));
     private static final int GZIP_COMPRESSION_LEVEL = 3;
 
     private final OkHttpClient httpClient;

apm-agent-core/src/main/java/co/elastic/apm/report/ReporterConfiguration.java

@@ -7,9 +7,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -23,6 +23,7 @@
 import org.stagemonitor.configuration.ConfigurationOptionProvider;
 import org.stagemonitor.configuration.converter.UrlValueConverter;
 
+import javax.annotation.Nullable;
 import java.net.URL;
 
 public class ReporterConfiguration extends ConfigurationOptionProvider {
@@ -81,6 +82,7 @@ public class ReporterConfiguration extends ConfigurationOptionProvider {
         .dynamic(true)
         .buildWithDefault(500);
 
+    @Nullable
     public String getSecretToken() {
         return secretToken.get();
     }

apm-agent-core/src/test/java/co/elastic/apm/impl/ElasticApmTracerTest.java

@@ -7,9 +7,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -259,4 +259,12 @@ public void stop() {
         tracer.stop();
         assertThat(stopCalled).isTrue();
     }
+
+    @Test
+    void testSpanWithoutTransaction() {
+        try (Span span = tracerImpl.startSpan()) {
+            assertThat(span.isSampled()).isFalse();
+        }
+
+    }
 }