because JDK 20 Valhalla support is not yet available in IntelliJ IDEA

JAVA_VERSION = 20 JAVAC = /home/user/downloads/jdk-20-vahalla-20-75/bin/javac JAVA = /home/user/downloads/jdk-20-vahalla-20-75/bin/java

JAVA_COMPILE_OPTIONS = --enable-preview --release $(JAVA_VERSION) JAVA_OPTIONS = --enable-preview

JAVA_MAIN_CLASS = org.example.Database JAVA_SOURCES = $(wildcard src/main/java/**/**/*.java) JAVA_CLASSES =$(patsubst src/main/java/%.java, target/classes/%.class, $(JAVA_SOURCES))

Compile the Java source files

compile: $(JAVA_CLASSES)$(info Java source files: $(JAVA_SOURCES))$(info Java class files: $(JAVA_CLASSES))

Run the Java main class

run: compile $(JAVA)$(JAVA_OPTIONS) -cp target/classes $(JAVA_MAIN_CLASS)

Clean the target directory

clean: rm -rf target

Compile the Java source files

target/classes/%.class: src/main/java/%.java $(JAVAC)$(JAVA_COMPILE_OPTIONS) -d target/classes $<

Create the target directory

target/classes: mkdir -p target/classes

Make the target directory a dependency of the Java class files

$(JAVA_CLASSES): target/classes

Make the target directory a dependency of the compile target

compile: target/classes

Ditto...

clean: target/classes run: target/classes default: target/classes

default: run