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Java makes me sad since it needs wrapper classes for ArrayLists. How would I go about adding a byte[] to a ArrayList<Byte[]>?
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A byte in Java is 8 bits. It is a primitive data type, meaning it comes packaged with Java. Bytes can hold values from -128 to 127. No special tasks are needed to use it; simply declare a byte variable and you are off to the races.
The recommended solution to concatenate two or more byte arrays is using ByteArrayOutputStream . The idea is to write bytes from each of the byte arrays to the output stream, and then call toByteArray() to get the current contents of the output stream as a byte array.
Similarly, the BigInteger class has a longValue() method to convert a byte array to a long value: long value = new BigInteger(bytes). longValue();
Arrays. fill(). This method assigns the required byte value to the byte array in Java.
LOL thought I had to wrap everything. ArrayList<byte[]> works. Thanks Yishai.
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You have to wrap any primitives to use them in a context that requires an object. But a byte[] is not a primitive. It's an array of bytes, and an array is an object.
Just to clarify: Do you really want an ArrayList of arrays of bytes, i.e. effectively a two-dimensional array? Or do you really simply want an ArrayList of bytes? In that case, you would have to wrap the bytes in Bytes to put them in the ArrayList.
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Just for the purpose of others searching for this, if you have Apache Commons on your classpath, you can do something like the following to get Byte[] back (documentation]:
Byte[] result = ArrayUtils.toObject(byte[]);
ArrayList works only, if you do not require the results of hashCode() and equals() on this list.
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