javac（compile）和java（run）包在不同的目录结构级别上工作？

Question

I just noticed that for compiling I need to specify the exact path from my current location for the java source files that needs to be compiled, but to run the class file, all I need is the class qualified name.

Does the java command recursively look inside all the folders in my current directory to find the class and execute it?

if so why doesn't the javac work similarly but expects to have the absolute path?

From my project folder location,

javac -cp ".:/Users/page/.m2/repository/org/slf4j/slf4j-api/1.7.5/slf4j-api-1.7.5.jar:target/classes" src/main/java/app/Assignment04.java


java -cp ".:/Users/page/.m2/repository/org/slf4j/slf4j-api/1.7.5/slf4j-api-1.7.5.jar:target/classes" app.Assignment04

EDIT: when I explicitly mentioned path like this; java -cp ".:/Users/page/.m2/repository/org/slf4j/slf4j-api/1.7.5/slf4j-api-1.7.5.jar:src/main/java/com/scg/util/*:src/main/java/com/scg/domain/*:src/main/java/app/*" app.Assignment04

I get Error: Could not find or load main class app.Assignment04

although I give src/main/java/app/ in my classpath

Answer 1

-cp ".:/Users/page/.m2/repository/org/slf4j/slf4j-api/1.7.5/slf4j-api-1.7.5.jar:target/classes"

is the important bit. When compiling the classpath argument is not considered for the source files themselves (only to resolve dependencies).

When running with java the named class is sought on the classpath, which includes the target directory explicitly as target/classes . Thus that location is also used to find the class in question.