メソッドの引数などのクラスロードのタイミングの調査

0.MethodClassLoadingTesting.java

import java.util.Objects;

class MethodClassLoadingTesting {
    static {
        System.out.println("        MethodClassLoadingTesting loaded");
    }

    public static void main(String[] args) {
        System.out.println("loading MethodHolderClass");
        MethodHolderClass.loader();
        System.out.println("finish MethodHolderClass");

        System.out.println("calling theMethod1 with null");
        MethodHolderClass.theMethod1(null);
        System.out.println("finish theMethod1 with null");

        System.out.println("calling theMethod1 with instance");
        MethodHolderClass.theMethod1(new MethodParameterClass1());
        System.out.println("finish theMethod1 with instance");

        System.out.println("calling theMethod2 with null");
        MethodHolderClass.theMethod2(null);
        System.out.println("finish theMethod2 with null");

        System.out.println("calling theMethod2 with instance");
        MethodHolderClass.theMethod2(new MethodParameterClass2());
        System.out.println("finish theMethod2 with instance");
    }
}

class MethodHolderClass {
    static MethodReturningClass1 theMethod1(MethodParameterClass1 param) {
        System.out.println("    theMethod1 was called");
        MethodInsideUsingClass.loader();
        return null;
    }

    static MethodReturningClass2 theMethod2(MethodParameterClass2 param) {
        System.out.println("    theMethod2 was called");
        MethodInsideUsingClass.loader();
        return null;
    }

    static void loader() {}

    static {
        System.out.println("        MethodHolderClass loaded");
    }
}

class MethodReturningClass1 {
    static {
        System.out.println("        MethodReturningClass1 loaded");
    }
}

class MethodReturningClass2 {
    static {
        System.out.println("        MethodReturningClass2 loaded");
    }
}

class MethodParameterNullClass1 {
    static {
        System.out.println("        MethodParameterNullClass1 loaded");
    }
}

class MethodParameterNullClass2 {
    static {
        System.out.println("        MethodParameterNullClass2 loaded");
    }
}

class MethodParameterClass1 {
    static {
        System.out.println("        MethodParameterClass1 loaded");
    }
}

class MethodParameterClass2 {
    static {
        System.out.println("        MethodParameterClass2 loaded");
    }
}

class MethodInsideUsingClass {
    static void loader() {}
    static {
        System.out.println("        MethodInsideUsingClass loaded");
    }
}

2.actual-log.txt

        MethodClassLoadingTesting loaded
loading MethodHolderClass
        MethodHolderClass loaded
finish MethodHolderClass
calling theMethod1 with null
    theMethod1 was called
        MethodInsideUsingClass loaded
finish theMethod1 with null
calling theMethod1 with instance
        MethodParameterClass1 loaded
    theMethod1 was called
finish theMethod1 with instance
calling theMethod2 with null
    theMethod2 was called
finish theMethod2 with null
calling theMethod2 with instance
        MethodParameterClass2 loaded
    theMethod2 was called
finish theMethod2 with instance

3.without-MethodParameterClass2.txt

bash-3.2$ javac MethodClassLoadingTesting.java
bash-3.2$ rm MethodParameterClass2.class
bash-3.2$ java MethodClassLoadingTesting
        MethodClassLoadingTesting loaded
loading MethodHolderClass
        MethodHolderClass loaded
finish MethodHolderClass
calling theMethod1 with null
    theMethod1 was called
        MethodInsideUsingClass loaded
finish theMethod1 with null
calling theMethod1 with instance
        MethodParameterClass1 loaded
    theMethod1 was called
finish theMethod1 with instance
calling theMethod2 with null
    theMethod2 was called
finish theMethod2 with null
calling theMethod2 with instance
Exception in thread "main" java.lang.NoClassDefFoundError: MethodParameterClass2
	at MethodClassLoadingTesting.main(MethodClassLoadingTesting.java:26)
Caused by: java.lang.ClassNotFoundException: MethodParameterClass2
	at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
	... 1 more
bash-3.2$

4.enviorments.txt

bash-3.2$ uname -v
Darwin Kernel Version 20.2.0: Wed Dec  2 20:39:59 PST 2020; root:xnu-7195.60.75~1/RELEASE_X86_64
bash-3.2$ java -version
openjdk version "1.8.0_275"
OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_275-b01)
OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.275-b01, mixed mode)
bash-3.2$ system_profiler SPHardwareDataType
Hardware:

    Hardware Overview:

      Model Name: iMac
      Model Identifier: iMac17,1
      Processor Name: Quad-Core Intel Core i5
      Processor Speed: 3.3 GHz
      Number of Processors: 1
      Total Number of Cores: 4
      L2 Cache (per Core): 256 KB
      L3 Cache: 6 MB
      Memory: 32 GB
      System Firmware Version: 429.60.3.0.0
      SMC Version (system): 2.34f3
      Serial Number (system): <privacy>
      Hardware UUID: <privacy>
      Provisioning UDID: <privacy>

bash-3.2$