title: What is the default GC used in Java 1.7 (45) on Linux
body: <p>Our JVM is HotSpot -64-Bit Server (mixed mode) on Linux.</p>
  
  <p>Looking at the GC logs it seems that ParallelGC is the default. Why isn't CMS the default GC algo? Is it due to the lack of compaction? But that would be the case with parallelGC too.</p>
  
  <p>We notice that a FullGC is not fired even when the heap reaches 75% capacity. When does a full GC fired for the default GC in java 1.7?</p>