[pulsar-functions] fix words error and remove not use import java cla…

…ss (apache#3791)

### Motivation
   when I study and read this module code , I fix some error like:
1. words error, such as JaveInstance -> JavaInstance, Recieved -> Received,  Unknwon -> Unknown, alterted -> alterted, Updare -> Update, etc.
2. remove not use import java class.
3. duplicated code in this  java class I extract method. 
4. javadoc  styles are consistent (not required)

### Modifications

minor fix up in pulsar-functions module

pulsar-functions/api-java/src/main/java/org/apache/pulsar/functions/api/Context.java

@@ -34,43 +34,50 @@
  */
 public interface Context {
     /**
-     * Access the record associated with the current input value
+     * Access the record associated with the current input value.
+     *
      * @return
      */
     Record<?> getCurrentRecord();
 
     /**
-     * Get a list of all input topics
+     * Get a list of all input topics.
+     *
      * @return a list of all input topics
      */
     Collection<String> getInputTopics();
 
     /**
-     * Get the output topic of the function
+     * Get the output topic of the function.
+     *
      * @return output topic name
      */
     String getOutputTopic();
 
     /**
-     * Get output schema builtin type or custom class name
+     * Get output schema builtin type or custom class name.
+     *
      * @return output schema builtin type or custom class name
      */
     String getOutputSchemaType();
 
     /**
-     * The tenant this function belongs to
+     * The tenant this function belongs to.
+     *
      * @return the tenant this function belongs to
      */
     String getTenant();
 
     /**
-     * The namespace this function belongs to
+     * The namespace this function belongs to.
+     *
      * @return the namespace this function belongs to
      */
     String getNamespace();
 
     /**
-     * The name of the function that we are executing
+     * The name of the function that we are executing.
+     *
      * @return The Function name
      */
     String getFunctionName();
@@ -96,19 +103,22 @@ public interface Context {
     int getNumInstances();
 
     /**
-     * The version of the function that we are executing
+     * The version of the function that we are executing.
+     *
      * @return The version id
      */
     String getFunctionVersion();
 
     /**
-     * The logger object that can be used to log in a function
+     * The logger object that can be used to log in a function.
+     *
      * @return the logger object
      */
     Logger getLogger();
 
     /**
-     * Increment the builtin distributed counter refered by key
+     * Increment the builtin distributed counter referred by key.
+     *
      * @param key The name of the key
      * @param amount The amount to be incremented
      */
@@ -123,7 +133,7 @@ public interface Context {
     long getCounter(String key);
 
     /**
-     * Updare the state value for the key.
+     * Update the state value for the key.
      *
      * @param key name of the key
      * @param value state value of the key
@@ -139,42 +149,47 @@ public interface Context {
     ByteBuffer getState(String key);
 
     /**
-     * Get a map of all user-defined key/value configs for the function
+     * Get a map of all user-defined key/value configs for the function.
+     *
      * @return The full map of user-defined config values
      */
     Map<String, Object> getUserConfigMap();
 
     /**
-     * Get any user-defined key/value
+     * Get any user-defined key/value.
+     *
      * @param key The key
      * @return The Optional value specified by the user for that key.
      */
     Optional<Object> getUserConfigValue(String key);
 
     /**
-     * Get any user-defined key/value or a default value if none is present
+     * Get any user-defined key/value or a default value if none is present.
+     *
      * @param key
      * @param defaultValue
      * @return Either the user config value associated with a given key or a supplied default value
      */
     Object getUserConfigValueOrDefault(String key, Object defaultValue);
 
     /**
-     * Get the secret associated with this key
+     * Get the secret associated with this key.
+     *
      * @param secretName The name of the secret
      * @return The secret if anything was found or null
      */
     String getSecret(String secretName);
 
     /**
-     * Record a user defined metric
+     * Record a user defined metric.
+     *
      * @param metricName The name of the metric
      * @param value The value of the metric
      */
     void recordMetric(String metricName, double value);
 
     /**
-     * Publish an object using serDe for serializing to the topic
+     * Publish an object using serDe for serializing to the topic.
      *
      * @param topicName
      *            The name of the topic for publishing
@@ -187,7 +202,8 @@ public interface Context {
     <O> CompletableFuture<Void> publish(String topicName, O object, String schemaOrSerdeClassName);
 
     /**
-     * Publish an object to the topic using default schemas
+     * Publish an object to the topic using default schemas.
+     *
      * @param topicName The name of the topic for publishing
      * @param object The object that needs to be published
      * @return A future that completes when the framework is done publishing the message

pulsar-functions/api-java/src/main/java/org/apache/pulsar/functions/api/Function.java

@@ -29,6 +29,7 @@
 public interface Function<I, O> {
     /**
      * Process the input.
+     *
      * @return the output
      */
     O process(I input, Context context) throws Exception;

pulsar-functions/api-java/src/main/java/org/apache/pulsar/functions/api/Record.java

@@ -28,21 +28,21 @@
 public interface Record<T> {
 
     /**
-     * If the record originated from a topic, report the topic name
+     * If the record originated from a topic, report the topic name.
      */
     default Optional<String> getTopicName() {
         return Optional.empty();
     }
 
     /**
-     * Return a key if the key has one associated
+     * Return a key if the key has one associated.
      */
     default Optional<String> getKey() {
         return Optional.empty();
     }
 
     /**
-     * Retrieves the actual data of the record
+     * Retrieves the actual data of the record.
      *
      * @return The record data
      */
@@ -85,19 +85,19 @@ default Map<String, String> getProperties() {
     }
 
     /**
-     * Acknowledge that this record is fully processed
+     * Acknowledge that this record is fully processed.
      */
     default void ack() {
     }
 
     /**
-     * To indicate that this record has failed to be processed
+     * To indicate that this record has failed to be processed.
      */
     default void fail() {
     }
 
     /**
-     * To support message routing on a per message basis
+     * To support message routing on a per message basis.
      *
      * @return The topic this message should be written to
      */

pulsar-functions/api-java/src/main/java/org/apache/pulsar/functions/api/WindowContext.java

@@ -29,25 +29,29 @@
 public interface WindowContext {
 
     /**
-     * The tenant this function belongs to
+     * The tenant this function belongs to.
+     *
      * @return the tenant this function belongs to
      */
     String getTenant();
 
     /**
-     * The namespace this function belongs to
+     * The namespace this function belongs to.
+     *
      * @return the namespace this function belongs to
      */
     String getNamespace();
 
     /**
-     * The name of the function that we are executing
+     * The name of the function that we are executing.
+     *
      * @return The Function name
      */
     String getFunctionName();
 
     /**
-     * The id of the function that we are executing
+     * The id of the function that we are executing.
+     *
      * @return The function id
      */
     String getFunctionId();
@@ -67,37 +71,43 @@ public interface WindowContext {
     int getNumInstances();
 
     /**
-     * The version of the function that we are executing
+     * The version of the function that we are executing.
+     *
      * @return The version id
      */
     String getFunctionVersion();
 
     /**
-     * Get a list of all input topics
+     * Get a list of all input topics.
+     *
      * @return a list of all input topics
      */
     Collection<String> getInputTopics();
 
     /**
-     * Get the output topic of the function
+     * Get the output topic of the function.
+     *
      * @return output topic name
      */
     String getOutputTopic();
 
     /**
-     * Get output schema builtin type or custom class name
+     * Get output schema builtin type or custom class name.
+     *
      * @return output schema builtin type or custom class name
      */
     String getOutputSchemaType();
 
     /**
-     * The logger object that can be used to log in a function
+     * The logger object that can be used to log in a function.
+     *
      * @return the logger object
      */
     Logger getLogger();
 
     /**
-     * Increment the builtin distributed counter refered by key
+     * Increment the builtin distributed counter referred by key.
+     *
      * @param key The name of the key
      * @param amount The amount to be incremented
      */
@@ -112,7 +122,7 @@ public interface WindowContext {
     long getCounter(String key);
 
     /**
-     * Updare the state value for the key.
+     * Update the state value for the key.
      *
      * @param key name of the key
      * @param value state value of the key
@@ -128,35 +138,39 @@ public interface WindowContext {
     ByteBuffer getState(String key);
 
     /**
-     * Get a map of all user-defined key/value configs for the function
+     * Get a map of all user-defined key/value configs for the function.
+     *
      * @return The full map of user-defined config values
      */
     Map<String, Object> getUserConfigMap();
 
     /**
-     * Get any user-defined key/value
+     * Get any user-defined key/value.
+     *
      * @param key The key
      * @return The Optional value specified by the user for that key.
      */
     Optional<Object> getUserConfigValue(String key);
 
     /**
-     * Get any user-defined key/value or a default value if none is present
+     * Get any user-defined key/value or a default value if none is present.
+     *
      * @param key
      * @param defaultValue
      * @return Either the user config value associated with a given key or a supplied default value
      */
     Object getUserConfigValueOrDefault(String key, Object defaultValue);
 
     /**
-     * Record a user defined metric
+     * Record a user defined metric.
+     *
      * @param metricName The name of the metric
      * @param value The value of the metric
      */
     void recordMetric(String metricName, double value);
 
     /**
-     * Publish an object using serDe for serializing to the topic
+     * Publish an object using serDe for serializing to the topic.
      *
      * @param topicName
      *            The name of the topic for publishing
@@ -169,7 +183,8 @@ public interface WindowContext {
     <O> CompletableFuture<Void> publish(String topicName, O object, String schemaOrSerdeClassName);
 
     /**
-     * Publish an object to the topic using default schemas
+     * Publish an object to the topic using default schemas.
+     *
      * @param topicName The name of the topic for publishing
      * @param object The object that needs to be published
      * @return A future that completes when the framework is done publishing the message

pulsar-functions/api-java/src/main/java/org/apache/pulsar/functions/api/WindowFunction.java

@@ -28,6 +28,7 @@
 public interface WindowFunction<I, O> {
     /**
      * Process the input.
+     *
      * @return the output
      */
     O process(Collection<Record<I>> input, WindowContext context) throws Exception;

pulsar-functions/api-java/src/test/java/org/apache/pulsar/functions/api/utils/JavaSerDeTest.java

@@ -25,7 +25,6 @@
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 import lombok.ToString;
-import org.apache.pulsar.functions.api.utils.JavaSerDe;
 import org.testng.annotations.Test;
 
 /**

pulsar-functions/instance/src/main/java/org/apache/pulsar/functions/instance/ContextImpl.java

@@ -66,7 +66,6 @@
 /**
  * This class implements the Context interface exposed to the user.
  */
-
 class ContextImpl implements Context, SinkContext, SourceContext {
     private InstanceConfig config;
     private Logger logger;
@@ -215,7 +214,7 @@ public String getFunctionName() {
 
     @Override
     public String getFunctionId() {
-        return config.getFunctionId().toString();
+        return config.getFunctionId();
     }
 
     @Override