mc_launcher.sh

#!/bin/bash

export LANG="en_US.UTF-8"

MC=/Users/steve/Minecraft

# Many of these options are explaiend here:
# http://stas-blogspot.blogspot.com/2011/07/most-complete-list-of-xx-options-for.html
# http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html
# http://blog.ragozin.info/2011/09/hotspot-jvm-garbage-collection-options.html

# Also see the following link for minecraft specific Java opts:
# http://pastebin.com/rY3gPVGE

# This ensures we're using the server vm.
JAVA_OPTS="-server"

# Define a specific max and min heap.  Do not use with -XX:+AggressiveHeap.
#JAVA_OPTS="$JAVA_OPTS -Xmx2G -Xms2G"
JAVA_OPTS="$JAVA_OPTS -Xmx4G -Xms512M"
#JAVA_OPTS="$JAVA_OPTS -XX:PermSize=128M -XX:MaxPermSize=128M -Xmn1600m"

# Modified Catalina benchmarks
JAVA_OPTS="$JAVA_OPTS -XX:PermSize=128m -XX:MaxPermSize=256m -XX:InitiatingHeapOccupancyPercent=80"

#### See: http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html#Imp
#### Oracle only recommends fiddling with thee on G1GC:

# For changing the marking threshold.
#JAVA_OPTS="$JAVA_OPTS -XX:InitiatingHeapOccupancyPercent"

# When you want to change the mixed garbage collections decisions.
#JAVA_OPTS="$JAVA_OPTS -XX:G1MixedGCLiveThresholdPercent -XX:G1HeapWastePercent"

# When you want to adjust the CSet for old regions.
#JAVA_OPTS="$JAVA_OPTS -XX:G1MixedGCCountTarget -XX:G1OldCSetRegionThresholdPercent"

# To increase the amount of reserve memory for "to-space".
#JAVA_OPTS="$JAVA_OPTS -XX:G1ReservePercent"

# Start the marking cycle earlier by reducing this.
#JAVA_OPTS="$JAVA_OPTS -XX:InitiatingHeapOccupancyPercent"

# To increase the number of parallel marking threads.
#JAVA_OPTS="$JAVA_OPTS -XX:ConcGCThreads"

#### End of Oracle recommenation

# This option instructs the JVM to push memory use to the limit (use with
# caution). This option appears to conflict with -XX:+UseG1GC.
#JAVA_OPTS="$JAVA_OPTS -XX:+AggressiveHeap"

# Reduce stack requirements (use with -XX:+AggressiveHeap).
#JAVA_OPTS="$JAVA_OPTS -Xss"

# Garbge Collector: G1GC.  Also, additional GC logging and disabled System.gc()
# calls, if any (usually, SMP only calls System.gc() when the "nogui" app parameter
# is absent).
JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCDetails -Xloggc:server_gc.log -XX:+UseG1GC"
#JAVA_OPTS="$JAVA_OPTS -XX:+DisableExplicitGC"

# Another garvage collector option (exclusive, pick G1GC or this).
#JAVA_OPTS="$JAVA_OPTS -Xloggc:server_gc.log -XX:+UseParallelOldGC -XX:+DisableExplicitGC"

# Sets a target for the maximum GC pause time. This is a soft goal, and the JVM
# will make its best effort to achieve it. Therefore, the pause time goal will
# sometimes not be met. The default value is 200 milliseconds.
#JAVA_OPTS="$JAVA_OPTS -XX:MaxGCPauseMillis=200"

# Percentage of the (entire) heap occupancy to start a concurrent GC cycle. It
# is used by G1 to trigger a concurrent GC cycle based on the occupancy of the
# entire heap, not just one of the generations. A value of 0 denotes 'do
# constant GC cycles'. The default value is 45 (i.e., 45% full or occupied).
# Use optimized versions of Get<Primitive>Field.
#JAVA_OPTS="$JAVA_OPTS -XX:InitiatingHeapOccupancyPercent=0"

# Use optimized versions of Get<Primitive>Field.
JAVA_OPTS="$JAVA_OPTS -XX:+UseFastAccessorMethods"

# This flag defaults to 1000, and can cause memory leaks.
#JAVA_OPTS="$JAVA_OPTS -XX:SoftRefLRUPolicyMSPerMB=0"

# This flag defaults to 1000, and can cause memory leaks.
#JAVA_OPTS="$JAVA_OPTS -XX:CMSInitiatingOccupancyFraction=80"

# Survivor target ratio. Java defaults to 50%, which wastes a lot of space. If
# you know how much you need (see below), you can set this value higher; this
# gives less waste and "better performance".
#JAVA_OPTS="$JAVA_OPTS -XX:TargetSurvivorRatio=90"

# Tells Java when to convert bytecode into compiled code.  Server defaults to
# something like 15,000, which is appropriate for something that will run for
# months, and horrible for something that will run for a few hours.  Non-server
# defaults to ... 1000? 1500? Much lower.
#JAVA_OPTS="$JAVA_OPTS -XX:CompileThreshold=300"

# Tells the garbage collector to break the job into many small parts.  May
# result in better performance. Essential on systems with few cores.
###JAVA_OPTS="$JAVA_OPTS -XX:+CMSIncrementalMode"

# Apparently, adjust the boundary between new and tenured as needed.
#JAVA_OPTS="$JAVA_OPTS -XX:+UseAdaptiveGCBoundary"

#JAVA_OPTS="$JAVA_OPTS -XX:MaxHeapFreeRatio=25 -XX:MinHeapFreeRatio=21"

# Enables caching of commonly allocated strings.
JAVA_OPTS="$JAVA_OPTS -XX:+UseStringCache"

# Optimize String concatenation operations where possible.
JAVA_OPTS="$JAVA_OPTS -XX:+OptimizeStringConcat"

# Enables the use of compressed pointers (object references represented as 32 bit
# offsets instead of 64-bit pointers) for optimized 64-bit performance with Java
# heap sizes less than 32gb.
# Also see: https://wikis.oracle.com/display/HotSpotInternals/CompressedOops
#JAVA_OPTS="$JAVA_OPTS -XX:+UseCompressedOops"

# Pre-touch the Java heap during JVM initialization. Every page of the heap is
# thus demand-zeroed during initialization rather than incrementally during
# application execution.
#JAVA_OPTS="$JAVA_OPTS -XX:+AlwaysPreTouch"

# Inline a previously compiled method only if its generated native code size is
# less than this.
# Default: 1000
#JAVA_OPTS="$JAVA_OPTS -XX:InlineSmallCode=8000"

# Print message about inlined methods (debug only).
#JAVA_OPTS="$JAVA_OPTS -XX:+PrintInlining"
#JAVA_OPTS="$JAVA_OPTS -XX:+PrintCompilation"
#JAVA_OPTS="$JAVA_OPTS -XX:+UnlockDiagnosticVMOptions -Xbatch"

# TESTING ONLY Force full gc at every Nth exit from the runtime system
# (N=FullGCALotInterval, default: 1)
#XXXJAVA_OPTS="$JAVA_OPTS -XX:+FullGCALot"

# Maximum number of bytecode instructions in a method which gets inlined.
#JAVA_OPTS="$JAVA_OPTS -XX:MaxInlineSize=270"

# Maximum number of bytecode instructions in a frequently executed method which
# gets inlined.
#JAVA_OPTS="$JAVA_OPTS -XX:FreqInlineSize=5000"

# Enable biased locking.  http://www.oracle.com/technetwork/java/tuning-139912.html#section4.2.5
JAVA_OPTS="$JAVA_OPTS -XX:+UseBiasedLocking"

# Use large page memory.  http://www.oracle.com/technetwork/java/javase/tech/largememory-jsp-137182.html
# [CONFLICT] Causes error: "Java HotSpot(TM) 64-Bit Server VM warning: Failed to reserve shared memory (errno = 22)."
#JAVA_OPTS="$JAVA_OPTS -XX:+UseLargePages"

# Enables the Java heap to take advantage of Non-Uniform-Memory-Architectures.
# JAVA will place data structures relevant to the thread which it owns /
# operates on, in memory locations closest to that particular processor.
# Depending on the environment, gains can be substantial. Intel market NUMA as
# Quick Path Interconnect.
# Also see: https://blogs.oracle.com/jonthecollector/entry/help_for_the_numa_weary
JAVA_OPTS="$JAVA_OPTS -XX:+UseNUMA"

# Disable class garbage collection. Use of this option will prevent memory
# recovery from loaded classes thus increasing overall memory usage. This could
# cause OutOfMemoryError to be thrown in some applications.
JAVA_OPTS="$JAVA_OPTS -Xnoclassgc"

# Use a byte[] for Strings which can be represented as pure ASCII. (Introduced
# in Java 6 Update 21 Performance Release)
# Option removed in Java 7.
#JAVA_OPTS="$JAVA_OPTS -XX:+UseCompressedStrings"

# Unroll loop bodies with server compiler intermediate representation node count
# less than this value. The limit used by the server compiler is a function of
# this value, not the actual value. The default value varies with the platform
# on which the JVM is running.
#JAVA_OPTS="$JAVA_OPTS -XX:LoopUnrollLimit=45"

#
# VM Triggers
#

JAVA_OPTS="$JAVA_OPTS -XX:OnError=$MC/scripts/jvm_on_error.sh"
JAVA_OPTS="$JAVA_OPTS -XX:OnOutOfMemoryError=$MC/scripts/jvm_on_out_of_memory.sh"

#JAVA_OPTS="$JAVA_OPTS -Dhttp.socksProxyHost=127.0.0.1 -Dhttp.socksProxyPort=9050"

# Causes the VM to pause at startup time and wait for the pause file to be
# removed (default: ./vm.paused.)
#JAVA_OPTS="$JAVA_OPTS -XX:PauseAtStartup"

screen -dmS minecraft nice -19 java $JAVA_OPTS -jar minecraft_server.jar nogui
#java $JAVA_OPTS -jar minecraft_server.jar nogui
#echo $JAVA_OPTS