Set it as a wood pickaxe. Still breaks instantly, but it cannot be broken in Adventure Mode. Can be configured to any tool you desire (except shears, in which case, just make it implement IShearable).
All devs and contributors should use the provided formatter settings.
If your IDE does not support the format, the rules are simple, it is the
default java formatting rules, with 200char line lengths and 1 extra
line after class definitions.
Mitchellbrine