Do all types of links protect the object from deletion?

No, not all. Only strong references protect an object from garbage collection. Weak, phantom, and soft references do not.

Here are their main differences:

• Strong reference: The standard reference in Java/Kotlin. If there is at least one strong reference to an object, it will not be collected by the garbage collector. It is the default.
• Soft reference: An object referenced by a soft reference can be collected by the garbage collector only if the JVM is in urgent need of memory. Useful for caching. Implemented via SoftReference.
• Weak reference: An object referenced by a weak reference can be collected by the garbage collector at any moment if there are no strong references to it. Used for implementing caches that do not block garbage collection. Implemented via WeakReference.
• Phantom reference: An object referenced by a phantom reference has already been queued for garbage collection (finalize has been called or not overridden), but has not yet been fully removed. Used for tracking the collection process and resource release. Implemented via PhantomReference.

Example of a weak reference:

// Create an object
Object myObject = new Object();

// Create a weak reference to the object
WeakReference<Object> weakRef = new WeakReference<>(myObject);

// Make the strong reference null, now the object is only reachable via the weak reference
myObject = null;

// At some point, the garbage collector may delete the object if it needs memory.
// weakRef.get() will return null if the object has been collected.