Here you can find the source of format(long size)
public static String format(long size)
//package com.java2s; /*//from w ww .j av a 2 s .co m * Copyright (C) 2015 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.text.DecimalFormat; public class Main { public static String format(long size) { DecimalFormat df = new DecimalFormat("0.00"); float sizeK = 1024.0f; float sizeM = sizeK * sizeK; float sizeG = sizeM * sizeK; float sizeT = sizeG * sizeK; if (size < sizeM) { return df.format(size / sizeK) + " KB"; } if (size < sizeG) { return df.format(size / sizeM) + " MB"; } if (size < sizeT) { return df.format(size / sizeG) + " GB"; } return ""; } }