public class ConfigReader {
public static void main(String[] args) {
try {
Properties properties = new Properties();
properties.load(ConfigReader.class.getClassLoader().getResourceAsStream("config.properties"));
Class<?> clazz = Class.forName(properties.getProperty("class.name"));
Object instance = clazz.getDeclaredConstructor().newInstance();
Field field = clazz.getDeclaredField(properties.getProperty("field.name"));
field.setAccessible(true);
field.set(instance, properties.getProperty("new.field.value"));
} catch (Exception e) {
e.printStackTrace();
}
}
}
class.name=com.example.Config
field.name=configValue
new.field.value=New Value
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
interface Hello {
void sayHello();
}
class HelloImpl implements Hello {
@Override
public void sayHello() {
System.out.println("Hello, World!");
}
}
public class DynamicProxyExample {
public static void main(String[] args) {
Hello hello = (Hello) Proxy.newProxyInstance(
DynamicProxyExample.class.getClassLoader(),
new Class[]{Hello.class},
new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("Before method invocation...");
Object result = method.invoke(new HelloImpl(), args);
System.out.println("After method invocation...");
return result;
}
});
hello.sayHello();
}
}
import java.lang.reflect.Field;
class MyClass {
private String privateField = "privateValue";
public void setPrivateField(String privateField) {
this.privateField = privateField;
}
public String getPrivateField() {
return privateField;
}
}
public class ReflectionTestUtils {
public static void main(String[] args) {
MyClass obj = new MyClass();
try {
Field field = MyClass.class.getDeclaredField("privateField");
field.setAccessible(true);
field.set(obj, "newValue");
} catch (Exception e) {
e.printStackTrace();
}
obj.setPrivateField("anotherNewValue");
}
}
