Do I have to install JAVA?

Do I really need to install JAVA on my desktop (Pop!_Os)?
Do I really need to install JAVA to run canu?
Complete documentation at http://canu.readthedocs.org/en/latest/
jjf@system76-pc:~$ canu-2.1.1/bin/canu  -p SRR12695182 -d FSL_J1_175  genomeSize=1.4m -nanopore Downloads/sra_data.fastq.gz
-- canu 2.1.1
--
-- CITATIONS
--
-- For 'standard' assemblies of PacBio or Nanopore reads:
--   Koren S, Walenz BP, Berlin K, Miller JR, Phillippy AM.
--   Canu: scalable and accurate long-read assembly via adaptive k-mer weighting and repeat separation.
--   Genome Res. 2017 May;27(5):722-736.
--   http://doi.org/10.1101/gr.215087.116
-- 
-- Read and contig alignments during correction and consensus use:
--   Šošic M, Šikic M.
--   Edlib: a C/C ++ library for fast, exact sequence alignment using edit distance.
--   Bioinformatics. 2017 May 1;33(9):1394-1395.
--   http://doi.org/10.1093/bioinformatics/btw753
-- 
-- Overlaps are generated using:
--   Berlin K, et al.
--   Assembling large genomes with single-molecule sequencing and locality-sensitive hashing.
--   Nat Biotechnol. 2015 Jun;33(6):623-30.
--   http://doi.org/10.1038/nbt.3238
-- 
--   Myers EW, et al.
--   A Whole-Genome Assembly of Drosophila.
--   Science. 2000 Mar 24;287(5461):2196-204.
--   http://doi.org/10.1126/science.287.5461.2196
-- 
-- Corrected read consensus sequences are generated using an algorithm derived from FALCON-sense:
--   Chin CS, et al.
--   Phased diploid genome assembly with single-molecule real-time sequencing.
--   Nat Methods. 2016 Dec;13(12):1050-1054.
--   http://doi.org/10.1038/nmeth.4035
-- 
-- Contig consensus sequences are generated using an algorithm derived from pbdagcon:
--   Chin CS, et al.
--   Nonhybrid, finished microbial genome assemblies from long-read SMRT sequencing data.
--   Nat Methods. 2013 Jun;10(6):563-9
--   http://doi.org/10.1038/nmeth.2474
-- 
-- CONFIGURE CANU
--
readline() on closed filehandle F at /home/jjf/canu-2.1.1/bin/../lib/site_perl/canu/Defaults.pm line 1125.
-- Failed Java version check.
--
-- Trying again.
--
readline() on closed filehandle F at /home/jjf/canu-2.1.1/bin/../lib/site_perl/canu/Defaults.pm line 1125.
-- Failed Java version check.
--
-- Trying again.
--
--
-- WARNING:
-- WARNING:  Failed to run gnuplot using command 'gnuplot'.
-- WARNING:  Plots will be disabled.
-- WARNING:
--

usage:   canu [-version] [-citation] \
              [-haplotype | -correct | -trim | -assemble | -trim-assemble] \
              [-s <assembly-specifications-file>] \
               -p <assembly-prefix> \
               -d <assembly-directory> \
               genomeSize=<number>[g|m|k] \
              [other-options] \
              [-haplotype{NAME} illumina.fastq.gz] \
              [-corrected] \
              [-trimmed] \
              [-pacbio |
               -nanopore |
               -pacbio-hifi] file1 file2 ...

example: canu -d run1 -p godzilla genomeSize=1g -nanopore-raw reads/*.fasta.gz 

  To restrict canu to only a specific stage, use:
    -haplotype     - generate haplotype-specific reads
    -correct       - generate corrected reads
    -trim          - generate trimmed reads
    -assemble      - generate an assembly
    -trim-assemble - generate trimmed reads and then assemble them

  The assembly is computed in the -d <assembly-directory>, with output files named
  using the -p <assembly-prefix>.  This directory is created if needed.  It is not
  possible to run multiple assemblies in the same directory.

  The genome size should be your best guess of the haploid genome size of what is being
  assembled.  It is used primarily to estimate coverage in reads, NOT as the desired
  assembly size.  Fractional values are allowed: '4.7m' equals '4700k' equals '4700000'

  Some common options:
    useGrid=string
      - Run under grid control (true), locally (false), or set up for grid control
        but don't submit any jobs (remote)
    rawErrorRate=fraction-error
      - The allowed difference in an overlap between two raw uncorrected reads.  For lower
        quality reads, use a higher number.  The defaults are 0.300 for PacBio reads and
        0.500 for Nanopore reads.
    correctedErrorRate=fraction-error
      - The allowed difference in an overlap between two corrected reads.  Assemblies of
        low coverage or data with biological differences will benefit from a slight increase
        in this.  Defaults are 0.045 for PacBio reads and 0.144 for Nanopore reads.
    gridOptions=string
      - Pass string to the command used to submit jobs to the grid.  Can be used to set
        maximum run time limits.  Should NOT be used to set memory limits; Canu will do
        that for you.
    minReadLength=number
      - Ignore reads shorter than 'number' bases long.  Default: 1000.
    minOverlapLength=number
      - Ignore read-to-read overlaps shorter than 'number' bases long.  Default: 500.
  A full list of options can be printed with '-options'.  All options can be supplied in
  an optional sepc file with the -s option.

  For TrioCanu, haplotypes are specified with the -haplotype{NAME} option, with any
  number of haplotype-specific Illumina read files after.  The {NAME} of each haplotype
  is free text (but only letters and numbers, please).  For example:
    -haplotypeNANNY nanny/*gz
    -haplotypeBILLY billy1.fasta.gz billy2.fasta.gz

  Reads can be either FASTA or FASTQ format, uncompressed, or compressed with gz, bz2 or xz.

  Reads are specified by the technology they were generated with, and any processing performed.

  [processing]
    -corrected
    -trimmed

  [technology]
    -pacbio      <files>
    -nanopore    <files>
    -pacbio-hifi <files>

Complete documentation at http://canu.readthedocs.org/en/latest/

ERROR:  mhap overlapper requires java version at least 1.8.0; you have unknown (from 'java').
ERROR:  'java -Xmx1g -showversion' reports:

jjf@system76-pc:~$
marbl / canu

Do I have to install JAVA? #1891
