when(toolchainFactoryBasicType.createDefaultToolchain()).thenReturn(Optional.of(basicToolchain));
        org.apache.maven.api.Toolchain rareToolchain = mock(org.apache.maven.api.Toolchain.class);
        when(toolchainFactoryRareType.createDefaultToolchain()).thenReturn(Optional.of(rareToolchain));

        // execute

     *
     * @return Optional containing the default toolchain if available
     * @throws ToolchainFactoryException if default toolchain creation fails
     */
    @Nonnull
    Optional<Toolchain> createDefaultToolchain() throws ToolchainFactoryException;

    /**
     * Returns the default instance of the particular type of toolchain, can return <code>null</code>
     * if not applicable.
     * TODO keep around??
     **/
    ToolchainPrivate createDefaultToolchain();

                }

                @Nonnull
                @Override
                public Optional<org.apache.maven.api.Toolchain> createDefaultToolchain()
                        throws ToolchainFactoryException {
                    return Optional.ofNullable(v3Factory.createDefaultToolchain())
                            .map(ToolchainManagerFactory.this::getToolchainV4);
                }
            });
        }

                    "Non-existing JDK home configuration at " + normal.toAbsolutePath());
        }

        return jtc;
    }

    @Override
    public ToolchainPrivate createDefaultToolchain() {
        // not sure it's necessary to provide a default toolchain here.
        // only version can be eventually supplied.
        return null;
    }

    protected Logger getLogger() {