fix(doc): docker build add jdk 8 reminder (#35)

Author: Sunny6889

tools/docker/README.md

@@ -5,6 +5,9 @@ If you encounter any problems during the build or testing process, please refer
 
 ## Prerequisites
 
+- Docker
+- JDK 8 (required by Gradle)
+
 Follow the [getting-started](https://github.com/tronprotocol/tron-docker/blob/main/README.md#getting-started) guide to download Docker and the tron-docker repository. Then, navigate to the gradlew directory.
 ```
 cd ./tools/gradlew

tools/trond/cmd/docker/build.go

@@ -17,7 +17,8 @@ var buildCmd = &cobra.Command{
 			Build java-tron docker image locally. The master branch of java-tron repository will be built by default, using jdk1.8.0_202.
 		`),
 	Example: heredoc.Doc(`
-			# Build java-tron docker image, defualt: tronprotocol/java-tron:latest
+			# Please ensure that JDK 8 is installed, as it is required to execute the commands below.
+			# Build java-tron docker image, default: tronprotocol/java-tron:latest.
 			$ ./trond docker build
 
 			# Build java-tron docker image with specified org, artifact and version

tools/trond/docs/trond_docker_build.md

@@ -14,7 +14,8 @@ trond docker build [flags]
 ### Examples
 
 ```
-# Build java-tron docker image, defualt: tronprotocol/java-tron:latest
+# Please ensure that JDK 8 is installed, as it is required to execute the commands below.
+# Build java-tron docker image, default: tronprotocol/java-tron:latest.
 $ ./trond docker build
 
 # Build java-tron docker image with specified org, artifact and version