Fix XRandR crash with no available displays and add JDK 8 compatibility for Buffer covariant return types - #170
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…ty for Buffer covariant return types Fix ArrayIndexOutOfBoundsException in XRandR when xrandr -q returns no connected screens by adding null/empty checks in findPrimary(), getResolutions(), ScreentoDisplayMode() and DisplayModetoScreen(). Fall back to default DisplayMode when no screen data is available. Add explicit (Buffer) casts on ByteBuffer/CharBuffer method calls (flip(), clear(), rewind(), limit(), position()) used in Java 9+ with covariant return types. When compiled with JDK 8 builds that include these backported signatures, the bytecode would reference ByteBuffer.flip()Ljava/nio/ByteBuffer; which does not exist at runtime on standard JDK 8 JVMs, causing NoSuchMethodError.
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问题 1: XRandR 空数组崩溃
当
xrandr -q返回无 connected 屏幕时，XRandR.java的内部数据结构均为空，导致ArrayIndexOutOfBoundsException：findPrimary()—screens[0]在空数组上越界getResolutions()—screens.get(name).clone()对 null 调用DisplayModetoScreen()/ScreentoDisplayMode()— 未处理findPrimary()返回 null修复：在所有方法中增加了空检查和 null 安全 fallback。
问题 2: JDK 8 NoSuchMethodError
ByteBuffer.flip()在 Java 9+ 中新增协变返回类型（返回ByteBuffer而非Buffer）。部分 JDK 8 发行版（如 Oracle JDK 1.8.0_441）在
rt.jar中包含了此协变签名，编译器据此生成字节码引用
ByteBuffer.flip()Ljava/nio/ByteBuffer;，而标准 JDK 8 虚拟机无此方法，运行时抛出
NoSuchMethodError。修复：对项目中所有
ByteBuffer/CharBuffer变量上的.flip()、.clear()、.rewind()、.limit(int)、.position(int)调用，通过(Buffer)转型强制编译出兼容 JDK 8 的字节码。修改统计：
验证：
ant jars— BUILD SUCCESSFUL，0 错误javap确认所有flip()调用目标为Buffer.flip()Ljava/nio/Buffer;XRandR所有公共方法均进行了空数组保护