$ javac src/OldWays.java && java OldWays     (21.0.10+7-Ubuntu-124.04)
  [init] building Expensive via eager static final
main starts (the eager value already exists)
first holder() call:
  [init] building Expensive via holder idiom
second holder() call:
first doubleChecked() call:
  [init] building Expensive via double-checked locking
second doubleChecked() call:

$ javac src/OldWays.java && java OldWays     (25.0.4.1+1-LTS)
  [init] building Expensive via eager static final
main starts (the eager value already exists)
first holder() call:
  [init] building Expensive via holder idiom
second holder() call:
first doubleChecked() call:
  [init] building Expensive via double-checked locking
second doubleChecked() call:

$ javac src/OldWays.java && java OldWays     (27+35)
  [init] building Expensive via eager static final
main starts (the eager value already exists)
first holder() call:
  [init] building Expensive via holder idiom
second holder() call:
first doubleChecked() call:
  [init] building Expensive via double-checked locking
second doubleChecked() call: