Replaces log4j with slf4j-simple and adds section for building native…

…-image with GraalVM to readme

README.md

@@ -195,6 +195,45 @@ Command line options are:
   -n,--num <arg> Number of tables to be generated.
   -t,--type <arg> Type of test file. Either sql or dot.
 
+## Native-image build with GraalVM
+
+If you want to leverage [GraalVM's](https://www.graalvm.org/) capability to build 
+[native-images](https://www.graalvm.org/latest/reference-manual/native-image/), 
+you can do so by following the below steps:
+
+- [Install GraalVM](https://www.graalvm.org/latest/docs/getting-started/#install-graalvm) on your system.
+- [Install the native-image](https://www.graalvm.org/latest/docs/getting-started/#native-image) functionality of `GraalVM`.
+- Depending on your OS, the linker might require `libfreetype.a` during the native-image build of this project;
+ in my case (Ubuntu 20.04) I did it via `sudo apt-get install libfreetype6-dev`.
+- If not already done, clone this project with `git`.
+- Add the driver of the database you want to build this native-image for to the dependency list in `pom.xml`.
+ E.g. for `PostgreSQL` I added:
+ ```
+ <dependency>
+ <groupId>org.postgresql</groupId>
+ <artifactId>postgresql</artifactId>
+ <version>42.3.0</version>
+ </dependency>
+ ```
+- From the root folder of the project build the app as usual with `mvn clean install`
+- Now, we will execute the application as we usually would, but with an agent attached 
+ that collects configurations for the native-image build and puts into the right folder:
+ ```
+ java -agentlib:native-image-agent=config-output-dir=app/src/main/resources/META-INF/native-image -jar app/target/dbvisualizer-app-1.0.0-SNAPSHOT-jar-with-dependencies.jar -driver org.postgresql.Driver -a PLANT -o app/target/postgresql_test.puml -d PostgreSQL -u <USER> -p <PASSWORD> -url <JDBC_URL> -r app/target/postgresql_test.html
+ ```
+ You will be able to see the files in `app/src/main/resources/META-INF/native-image`.
+- We run `mvn clean install` again. The first time we did it was just for being able to 
+ collect the required configurations. Now we build the app including the configurations. 
+- Switch into the target folder: `cd app/target`
+- Next, create the native-image from the jar we just built by executing:
+ ```
+ native-image -jar dbvisualizer-app-1.0.0-SNAPSHOT-jar-with-dependencies.jar
+ ```
+- To finally run the native-image, execute:
+ ```
+ ./dbvisualizer-app-1.0.0-SNAPSHOT-jar-with-dependencies -driver org.postgresql.Driver -a PLANT -o ../postgresql_test.puml -d PostgreSQL -u <USER> -p <PASSWORD> -url <JDBC_URL> -r ../postgresql_test.html
+ ```
+
 ## Ideas for future enhancements
 
 List of some features, which might be added in the future:

app/pom.xml

@@ -12,9 +12,6 @@
  <name>DB Visualizer App</name>
 
  <description>Creates a dot graph description from a database schema using JDBC</description>
- <properties>
- <log4j.version>2.19.0</log4j.version>
- </properties>
  <dependencies>
  <dependency>
  <groupId>org.junit.jupiter</groupId>
@@ -45,23 +42,8 @@
  </dependency>
  <dependency>
  <groupId>org.slf4j</groupId>
- <artifactId>slf4j-api</artifactId>
- <version>1.7.36</version>
- </dependency>
- <dependency>
- <groupId>org.apache.logging.log4j</groupId>
- <artifactId>log4j-core</artifactId>
- <version>${log4j.version}</version>
- </dependency>
- <dependency>
- <groupId>org.apache.logging.log4j</groupId>
- <artifactId>log4j-api</artifactId>
- <version>${log4j.version}</version>
- </dependency>
- <dependency>
- <groupId>org.apache.logging.log4j</groupId>
- <artifactId>log4j-slf4j-impl</artifactId>
- <version>${log4j.version}</version>
+ <artifactId>slf4j-simple</artifactId>
+ <version>2.0.7</version>
  </dependency>
  <dependency>
  <groupId>com.github.vandeseer</groupId>

app/src/main/resources/simplelogger.properties

@@ -0,0 +1,3 @@
+# https://www.slf4j.org/api/org/slf4j/simple/SimpleLogger.html
+
+org.slf4j.simpleLogger.defaultLogLevel=debug