How can you set the garbage collector (GC) configuration parameters in Java?

GC parameters are set using command-line options when launching the JVM. The most common options start with -XX:.

Examples of options:

• -Xms<size>: Initial heap size.
• -Xmx<size>: Maximum heap size.
• -XX:+<GCName>: Selecting the garbage collector. For example, -XX:+UseG1GC to enable G1 GC.
• -XX:NewRatio=<number>: Ratio of young generation to old generation (also "how many parts of old generation correspond to one part of young"). For example, -XX:NewRatio=2 means the old generation is twice as large as the young (1/3 heap - young, 2/3 - old).
• -XX:SurvivorRatio=<number>: Ratio of Eden space to each Survivor space. For example, -XX:SurvivorRatio=8 means the Eden space is 8 times larger than each Survivor space (1/10 of young generation - each Survivor).
• -XX:MaxMetaspaceSize=<size>: Maximum size of Metaspace.
• -XX:+PrintGCDetails: Output detailed information about each garbage collection.
• -XX:+PrintGCTimeStamps: Add timestamps to GC output.
• -XX:+UseConcMarkSweepGC: Use CMS collector (Deprecated in recent versions).
• -XX:+UseParallelGC: Use parallel collector for the young generation.

Example of launching an application with GC parameters:

java -Xms512m -Xmx2g -XX:+UseG1GC -XX:+PrintGCDetails -jar myapp.jar

Parameters may vary depending on the specific garbage collector and Java version. Oracle documentation is the primary source of information on available options.