public class FontMain {
    public static void main(String[] args) throws IOException, FontFormatException, InterruptedException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        File file = new File("/Users/cayun/PingFang.ttc");
        while (true) {
            run(file);
            Thread.sleep(1);
    private static void run(File file) throws IOException, FontFormatException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        BufferedImage blankImage = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = blankImage.createGraphics();
        Font font = Font.createFont(Font.TRUETYPE_FONT, file);
        font = font.deriveFont(12.0f);
        g.setFont(font);
        g.drawString("hello", 12, 12);
每次new Font()之后，调用g.drawString()方法都会在Non-Heap区域分配一块内存且不回收
g.drawString()的调用栈如下，
SunGraphics2D.drawString(String, int, int) -> ValidatePipe.drawString(SunGraphics2D, String, double, double) -> SunGraphics2D.getFontInfo() -> SunGraphics2D.checkFontInfo -> Font2D.getStrike(Font, AffineTransform, AffineTransform, int, int) -> Font2D.getStrike(FontStrikeDesc, boolean)->FileFont.createStrike(FontStrikeDesc) -> ... -> T2KFontScaler.<init>(Font2D, int, boolean, int) -> T2KFontScaler.initNativeScaler(...)
在调用栈中第二个标红的部分
new T2KFontScaler() 时会调用 T2KFontScaler.initNativeScaler()这个native方法，这个native方法会在Non-Heap部分分配内存，且之后也没有相应的回收机制。
demo代码&效果图
public class FontMain {
    public static void main(String[] args) throws IOException, FontFormatException, InterruptedException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, ClassNotFoundException, InstantiationException {
        File file = new File("/System/Library/Fonts/AquaKana.ttc");
        Font font = Font.createFont(Font.TRUETYPE_FONT, file);
        font = font.deriveFont(12.0f);
        BufferedImage blankImage = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = blankImage.createGraphics();
        g.setFont(font);
        // T2KFontScaler无法通过new的方式创建，此处使用反射创建
        Class clazz = Class.forName("sun.font.T2KFontScaler");
        Constructor constructor = clazz.getConstructor(Font2D.class, int.class, boolean.class, int.class);
        constructor.setAccessible(true);
        while (true) {
            constructor.newInstance(((SunGraphics2D) g).getFontInfo().font2D, 0, true, 80005872);
            Thread.sleep(1);
辅助证明：JDK已知bug
JDK-7074159 : run out of memory
为字体做个缓存
public class FontMain {
    private static Font font = null;
    private static Object lock = new Object();
    public static void main(String[] args) throws IOException, FontFormatException, InterruptedException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        File file = new File("/Users/cayun/PingFang.ttc");
        while (true) {
            run(file);
            Thread.sleep(1);
    private static void run(File file) throws IOException, FontFormatException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        BufferedImage blankImage = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = blankImage.createGraphics();
        if (font == null) {
            synchronized (lock) {
                if (font == null) {
                    font = Font.createFont(Font.TRUETYPE_FONT, file);
        font = font.deriveFont(12.0f);
        g.setFont(font);
        g.drawString("hello", 12, 12);
复制代码
原因详解
这个解决方法看起来有点奇怪，或许很容易就会有这样一个疑问：明明导致内存泄漏的是g.drawString()方法，却为何要对Font做缓存？
为了简单说明原因，我们先定义两种方案
方案1: 不使用缓存，就是原先会导致内存泄漏的方案
方案2: 对字体做缓存
现在来看调用栈部分第一个标红的位置，源码如下