This is the code I used to read the JCodings tables and create Java code for byte arrays.

gistfile1.rb

def read_int_at(file, index)
  (file[index] << 24) | (file[index+1] << 16) | (file[index+2] << 8) | file[index+3]
end

def hex_int_at(file, index, pad_length=0)
  rv = read_int_at(file, index).to_s(16)
  pad = "0" * (pad_length > rv.length ? (pad_length - rv.length) : 0)
  "0x#{pad}#{rv}"
end

#//    static final int CaseFold_From[] = readIntArray("CaseFold_From");
def generate_int_array(name, wrap=8, pad="    ")
  file = IO.read("#{name}.bin")
  puts "#{pad}static final int #{name}[] = {"
  a = []
  count = read_int_at(file, 0)
  1.upto(count) do |i| 
    a << hex_int_at(file, i*4)
    (puts("#{pad}#{pad}#{a.join(', ')}#{i == count ? '' : ','}"); a=[]) if a.length == wrap
  end
  puts("#{pad}#{pad}#{a.join(', ')}") unless a.empty?
  puts "#{pad}};\n\n"
end

#    static final int CaseFold_To[][] = readNestedIntArray("CaseFold_To");
def generate_nested_int_array(name, wrap=6, pad="    ")
  file = IO.read("#{name}.bin")
  puts "#{pad}static final int #{name}[][] = {"
  count1 = read_int_at(file, 0)
  offset = 4
  aa = []
  1.upto(count1) do |i|
    count2 = read_int_at(file, offset)
    offset += 4
    a = []
    1.upto(count2) do |j|
      a << hex_int_at(file, offset)
      offset += 4
    end
    aa << "{#{a.join(', ')}}"
    (puts("#{pad}#{pad}#{aa.join(', ')}#{i == count1 ? '' : ','}"); aa=[]) if aa.length == wrap
  end
  puts("#{pad}#{pad}#{aa.join(', ')}") unless aa.empty?
  puts "#{pad}};\n\n"
end

generate_int_array("CaseFold_From")
generate_nested_int_array("CaseFold_To")

generate_int_array("CaseFold_Locale_From")
generate_nested_int_array("CaseFold_Locale_To")

generate_int_array("CaseUnfold_11_From")
generate_nested_int_array("CaseUnfold_11_To")

generate_int_array("CaseUnfold_11_Locale_From")
generate_nested_int_array("CaseUnfold_11_Locale_To")

generate_nested_int_array("CaseUnfold_12")
generate_nested_int_array("CaseUnfold_12_Locale")

generate_nested_int_array("CaseUnfold_13")

Run this in the resources/tables directory of jcodings and capture the output to replace the readIntArray and readNestedIntArray calls.