This tracing starts with the root set, which consists of internal structures such as thread stacks and global references to objects.

这个跟踪以根集 开始，它由一些内部结构组成，比如线程栈和对象的全局引用。

youdao

All reachable (and therefore live) objects in the VM can be found by tracing this tree (or trees) of object references called the GC root tree.

VM里所有能获得的对象能够通过跟踪被叫做垃圾回收根树的对象参考树来找到。

youdao

A generational tracing collector starts from the root set, but does not traverse references that lead to objects in the older generation, which reduces the size of the object graph to be traced.

分代跟踪收集器从根集开始，但是并不遍历指向更老一代中对象的引用，这减少了要跟踪的对象图的大小。

youdao

Another new in-camera function is Clear Retouch, which makes it possible to erase unwanted objects or figures in an image by just tracing over them on monitor with a fingertip.

ENGADGET: Panasonic Lumix GF6 announced for the US, shipping in June for $600