Make messages in requireNonNull more descriptive

Updates usages of `Objects.requireNonNull` by adding some context to the
message so that users get a decent error message back rather than an empty
NullPointerException.

Signed-off-by: Vahid Ramezani <vahid.ramezani.2014@gmail.com>

Author: VahidRamezaniDB

spring-grpc-core/src/main/java/org/springframework/grpc/client/interceptor/DefaultDeadlineSetupClientInterceptor.java

@@ -37,7 +37,7 @@ public class DefaultDeadlineSetupClientInterceptor implements ClientInterceptor
 	private final Duration defaultDeadline;
 
 	public DefaultDeadlineSetupClientInterceptor(Duration defaultDeadline) {
-		this.defaultDeadline = requireNonNull(defaultDeadline, "defaultDeadline");
+		this.defaultDeadline = requireNonNull(defaultDeadline, "defaultDeadline must not be null");
 	}
 
 	@Override

spring-grpc-core/src/main/java/org/springframework/grpc/server/DefaultGrpcServerFactory.java

@@ -78,7 +78,7 @@ public class DefaultGrpcServerFactory<T extends ServerBuilder<T>> implements Grp
 
 	public DefaultGrpcServerFactory(String address, List<ServerBuilderCustomizer<T>> serverBuilderCustomizers) {
 		this.address = address;
-		this.serverBuilderCustomizers = Objects.requireNonNull(serverBuilderCustomizers, "serverBuilderCustomizers");
+		this.serverBuilderCustomizers = Objects.requireNonNull(serverBuilderCustomizers, "serverBuilderCustomizers must not be null");
 	}
 
 	public DefaultGrpcServerFactory(String address, List<ServerBuilderCustomizer<T>> serverBuilderCustomizers,

spring-grpc-core/src/main/java/org/springframework/grpc/server/lifecycle/GrpcServerLifecycle.java

@@ -61,8 +61,8 @@ public class GrpcServerLifecycle implements SmartLifecycle {
 	 */
 	public GrpcServerLifecycle(GrpcServerFactory factory, Duration shutdownGracePeriod,
 			ApplicationEventPublisher eventPublisher) {
-		this.factory = requireNonNull(factory, "factory");
-		this.shutdownGracePeriod = requireNonNull(shutdownGracePeriod, "shutdownGracePeriod");
+		this.factory = requireNonNull(factory, "factory must not be null");
+		this.shutdownGracePeriod = requireNonNull(shutdownGracePeriod, "shutdownGracePeriod must not be null");
 		this.eventPublisher = eventPublisher;
 	}
 

spring-grpc-core/src/main/java/org/springframework/grpc/server/lifecycle/GrpcServerLifecycleEvent.java

@@ -43,7 +43,7 @@ public abstract class GrpcServerLifecycleEvent extends ApplicationEvent {
 	 */
 	protected GrpcServerLifecycleEvent(final GrpcServerLifecycle lifecyle, final Clock clock, final Server server) {
 		super(lifecyle, clock);
-		this.server = requireNonNull(server, "server");
+		this.server = requireNonNull(server, "server must not be null");
 	}
 
 	/**
@@ -53,7 +53,7 @@ protected GrpcServerLifecycleEvent(final GrpcServerLifecycle lifecyle, final Clo
 	 */
 	protected GrpcServerLifecycleEvent(final GrpcServerLifecycle lifecyle, final Server server) {
 		super(lifecyle);
-		this.server = requireNonNull(server, "server");
+		this.server = requireNonNull(server, "server must not be null");
 	}
 
 	/**

spring-grpc-core/src/main/java/org/springframework/grpc/server/lifecycle/GrpcServerStartedEvent.java

@@ -49,7 +49,7 @@ public GrpcServerStartedEvent(final GrpcServerLifecycle lifecyle, final Clock cl
 			final String address, final int port) {
 
 		super(lifecyle, clock, server);
-		this.address = requireNonNull(address, "address");
+		this.address = requireNonNull(address, "address must not be null");
 		this.port = port;
 	}
 
@@ -65,7 +65,7 @@ public GrpcServerStartedEvent(final GrpcServerLifecycle lifecyle, final Server s
 			final int port) {
 
 		super(lifecyle, server);
-		this.address = requireNonNull(address, "address");
+		this.address = requireNonNull(address, "address must not be null");
 		this.port = port;
 	}