Can Java Instantiate Classes Using Only Their Names?

Is Class Instantiation by Name Possible in Java?

When dealing with class instantiation, circumstances may arise where the class name is known only as a string. To address this, Java offers two approaches to accomplish this task.

Method 1: Instantiating with a No-Arg Constructor

For classes with a no-argument constructor, Java allows object creation using the Class.forName() method to retrieve the class object and the newInstance() method to create an instance.

Class<?> clazz = Class.forName("java.util.Date");
Object date = clazz.newInstance();

Method 2: Handling Classes with or without No-Arg Constructor

A more comprehensive approach that covers all scenarios, including classes without no-argument constructors, involves querying the class object for its constructor and invoking newInstance() on it.

Class<?> clazz = Class.forName("com.foo.MyClass");
Constructor<?> constructor = clazz.getConstructor(String.class, Integer.class);
Object instance = constructor.newInstance("stringparam", 42);

Both methods utilize Java's reflection capabilities. However, it's crucial to handle exceptions that may arise during this process, such as:

• Class not found or cannot be loaded
• Lack of appropriate constructors
• Constructor throwing exceptions
• Non-public constructors
• Security manager preventing reflection

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