Question

I’m trying to compile my Java code with this Makefile. How ever when I run make, it compiles the code more than once.

Makefile:

.PHONY: all clean run

SOURCES = \
    Models/CustomException \
    Models/Forest \
    Models/ForestContainer \
    Models/Owner \
    Models/OwnerContainer \
    Models/Tree


SRC = $(addprefix src/, $(addsuffix .java, $(SOURCES)))
BIN = $(addprefix bin/, $(addsuffix .class, $(SOURCES)))

all: ${BIN}

clean:
    -rm -f ${BIN};

${BIN}: ${SRC}
    mkdir -p bin/Controllers;
    mkdir -p bin/Models;
    mkdir -p bin/Views;
    javac -d bin ${SRC};

run: all
    java -cp bin Program;

Output:

┌─( klim ) - ( ~/workspace/Forest-mvc )
└─> make

mkdir -p bin/Controllers;
mkdir -p bin/Models;
mkdir -p bin/Views;
javac -d bin src/Models/CustomException.java src/Models/Forest.java src/Models/ForestContainer.java src/Models/Owner.java src/Models/OwnerContainer.java src/Models/Tree.java;
mkdir -p bin/Controllers;
mkdir -p bin/Models;
mkdir -p bin/Views;
javac -d bin src/Models/CustomException.java src/Models/Forest.java src/Models/ForestContainer.java src/Models/Owner.java src/Models/OwnerContainer.java src/Models/Tree.java;
mkdir -p bin/Controllers;
mkdir -p bin/Models;
mkdir -p bin/Views;
javac -d bin src/Models/CustomException.java src/Models/Forest.java src/Models/ForestContainer.java src/Models/Owner.java src/Models/OwnerContainer.java src/Models/Tree.java;
mkdir -p bin/Controllers;
mkdir -p bin/Models;
mkdir -p bin/Views;
javac -d bin src/Models/CustomException.java src/Models/Forest.java src/Models/ForestContainer.java src/Models/Owner.java src/Models/OwnerContainer.java src/Models/Tree.java;
mkdir -p bin/Controllers;
mkdir -p bin/Models;
mkdir -p bin/Views;
javac -d bin src/Models/CustomException.java src/Models/Forest.java src/Models/ForestContainer.java src/Models/Owner.java src/Models/OwnerContainer.java src/Models/Tree.java;
mkdir -p bin/Controllers;
mkdir -p bin/Models;
mkdir -p bin/Views;
javac -d bin src/Models/CustomException.java src/Models/Forest.java src/Models/ForestContainer.java src/Models/Owner.java src/Models/OwnerContainer.java src/Models/Tree.java;

As you can see it runs the commands more than once, actually 6 times. The number of times it run the commands increase/decrease as number of SOURCES are added/removed

How can this be?

Answer 1

just add the main classes after javac.

${BIN}: ${SRC}
    javac -d bin -cp . Models/Tree.java

All the classes and the folders (packages) that depend of the main classes will be automatically compiled. Your make is compiling again and again some classes that have already been compiled.