Does garbage collection guarantee that a program will not run out of memory?

Garbage collection does not guarantee that a program will not run out of memory. As garbage collection is JVM dependent then It is possible for programs to use memory resources faster than they are garbage collected.Moreover garbage collection cannot be enforced,it is just suggested.Java guarantees that the finalize method will be run before an object is Garbage collected,it is called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

The garbage collection is uncontrolled, it means you cannot predict when it will happen, you thus cannot predict exactly when the finalize method will run. Once a variable is no longer referenced by anything it is available for garbage collection.You can suggest garbage collection with System.gc(), but this does not guarantee when it will happen.