Optimise code, use append(char) instead of append(String) #79

	# This workflow will build a Java project with Maven
	# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-maven

	# Note: Oracle JDK is only supported for JDK 17 and later

	name: Test with various JDK versions

	on: [push]

	jobs:
	test:
	runs-on: ubuntu-latest

	strategy:
	fail-fast: false
	matrix:
	distribution:
	- liberica
	- oracle
	java_version:
	- 8
	- 11
	- 17
	- 21
	exclude:
	- distribution: oracle
	java_version: 8
	- distribution: oracle
	java_version: 11

	services:
	monetdb_container:
	image: monetdb/dev-builds:Jun2023
	env:
	MDB_DAEMON_PASS: monetdb
	MDB_DB_ADMIN_PASS: monetdb
	ports:
	- 50000:50000

	steps:
	- uses: actions/checkout@v3

	- name: Set up JDK
	uses: actions/setup-java@v3
	with:
	java-version: ${{ matrix.java_version }}
	distribution: ${{ matrix.distribution }}

	- name: Build
	run: make

	- name: Create jar symlink
	run: ln -s monetdb-jdbc*.jar monetdb-jdbc.jar
	working-directory: jars

	- name: Run JDBC_API_Tester
	run: java -cp jars/monetdb-jdbc.jar:jars/jdbctests.jar JDBC_API_Tester 'jdbc:monetdb://localhost:50000/monetdb?user=monetdb&password=monetdb'

	- name: Run OnClientTester
	run: java -cp jars/monetdb-jdbc.jar:jars/jdbctests.jar OnClientTester 'jdbc:monetdb://localhost:50000/monetdb?user=monetdb&password=monetdb' -v

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