CODEWITHSUNDEEP
javaandroidmemory-management
Joe C
Joe C

Reputation: 2827

How does Java (Android) reuse free-ed memory?

I have an Android application that reads a lot of chunks of bytes one by one via network, then combine them into a large buffer. For example,

ByteArrayOutputStream outputStream = new ByteArrayOutputStream( );

while (i < 10) {
    // read is an API in a lib that returns byte[].
    byte[] bytes = API.read();
    outputStream.write(bytes);
    i++;
}

...

The question is about the memory for bytes. Is there a way to force Java to use the same chunk of byte for all reads? So it does not have to free and allocate memory too much? Will JAVA runtime optimize the case? Thanks.

Upvotes: 0

Views: 63

Answers (1)

nanofarad
nanofarad

Reputation: 41281

The byte[] will be garbage collected. It is not appropriate to use an NIO ByteBuffer in this case as you are getting byte[] anyway, though it could come in handy later.

With each loop iteration, a byte[] is being created and filled with data, read from into the stream, and then is no longer used. Once memory runs low (or earlier depending on how your JVM operates) the array will be deleted and the memory made available.

You need not worry about such things most of the time (unless you are concatenating tons of strings, which is extremely inefficient for this reason).

Upvotes: 3

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