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This article introduces the knowledge of "how to check memory leaks in java". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Memory leak scenario

Memory leaks are likely to occur when long-lifecycle objects hold references to short-lifecycle objects. Although short-lifecycle objects are no longer needed, they cannot be recycled because long-lifecycle objects hold their references. This is the scenario of memory leaks in Java.

1. CPU and memory usage during viewing:

Top-H-p 58527

2. Check the server memory.

Df-h check the disk condition du-h-- max-depth=1 file directory occupies resources.

3. View memory, cache, usage, and idle.

Free-m

S0C: the capacity of the first survivor (survival area) in the younger generation (in bytes)

S1C: the capacity of the second survivor (survival area) in the younger generation (in bytes)

S0U: the first survivor (survival area) of the younger generation currently uses space (bytes)

S1U: the second survivor (survival area) of the younger generation currently uses space (bytes)

EC: the capacity of Eden (Garden of Eden) in the younger generation (in bytes)

EU: the younger generation Eden (Garden of Eden) currently uses space (bytes)

Capacity of the OC:Old generation (bytes)

Space currently used by the OU:Old generation (bytes)

Capacity of PC:Perm (persistent generation) (bytes)

PU:Perm (persistent generation) currently uses space (bytes)

YGC: the number of gc in the younger generation from application startup to sampling

YGCT: the time taken by gc in the younger generation from application startup to sampling (s)

FGC: the number of old generation (full gc) gc from application startup to sampling

FGCT: time taken by old to replace (full gc) gc from application startup to sampling (s)

GCT: total time taken by gc from application startup to sampling (s)

4. Check the execution program information.

Jstack 2829 > 1.log grep-A 1roomjava.lang.Thread.State' jstack.log | wc-l

Download the heap file analysis code Dump.

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