If Java is a managed language then why do we have to manually close AutoCloseable resources? [duplicate]

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• Why do I need to use finally to close resources? 5 answers

In java, is it necessary for me to manually close all AutoCloseable and Closeable objects (whether through explicit call or relying on try-with-resources)?

Does the JVM not automatically clean up AutoCloseables and Closeables when they are no longer being referenced?

Is calling close explicitly (whether through explicit call or relying on try-with-resources) a manner of etiquette (i.e., recommended but not necessary) and is the reason to avoid indeterministic resource deallocation which would happen otherwise if one relied on the built in GC?