public void writeLines(Stream<? extends CharSequence> lines, String lineSeparator)
      throws IOException {
    writeLines(lines.iterator(), lineSeparator);
  }

  private void writeLines(Iterator<? extends CharSequence> lines, String lineSeparator)
      throws IOException {
    checkNotNull(lineSeparator);

    try (Writer out = openBufferedStream()) {
      while (lines.hasNext()) {

        StringWriter sWriter = new StringWriter();
        PrintWriter pWriter = new PrintWriter(sWriter);

        error.printStackTrace(pWriter);

        System.err.println("[error] " + content + System.lineSeparator() + System.lineSeparator() + sWriter);
    }

    /**
     * @see org.apache.maven.plugin.logging.Log#error(java.lang.Throwable)
     */
    @Override
    public void error(Throwable error) {

        super("Goal: " + goal + " already exists in the plugin descriptor for prefix: " + goalPrefix
                + System.lineSeparator() + "Existing implementation is: " + existingImplementation
                + System.lineSeparator() + "Conflicting implementation is: " + newImplementation);
    }

    String secondLine = "\\s*at " + ThrowablesTest.class.getName() + "\\..*";
    String moreLines = "(?:.*" + System.lineSeparator() + "?)*";
    String expected =
        firstLine + System.lineSeparator() + secondLine + System.lineSeparator() + moreLines;
    assertThat(getStackTraceAsString(e)).matches(expected);
  }

  public void testGetCausalChain() {

                    System.lineSeparator() + "Options:",
                    options,
                    HelpFormatter.DEFAULT_LEFT_PAD,
                    HelpFormatter.DEFAULT_DESC_PAD,
                    System.lineSeparator(),
                    false);
            pw2.flush();
            for (String s : sw.toString().split(System.lineSeparator())) {
                pw.accept(s);
            }

                    + "You have the following options to resolve this:" + System.lineSeparator()
                    + "  1. Preserve the model version by setting 'preserve.model.version=true' to generate a consumer POM with <modelVersion>4.2.0</modelVersion>, which supports mixins"
                    + System.lineSeparator()

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

class ToolchainsBuildingExceptionTest {
    private static final String LS = System.lineSeparator();

    @Test
    void testNoProblems() {
        ToolchainsBuildingException e = new ToolchainsBuildingException(Collections.emptyList());

    String secondLine = "\\s*at " + ThrowablesTest.class.getName() + "\\..*";
    String moreLines = "(?:.*" + System.lineSeparator() + "?)*";
    String expected =
        firstLine + System.lineSeparator() + secondLine + System.lineSeparator() + moreLines;
    assertThat(getStackTraceAsString(e)).matches(expected);
  }

  public void testGetCausalChain() {

/**
 * Common elements of artifact metadata.
 *
 */
@Deprecated
public abstract class AbstractArtifactMetadata implements ArtifactMetadata {
    private static final String LS = System.lineSeparator();

    protected Artifact artifact;

    protected AbstractArtifactMetadata(Artifact artifact) {
        this.artifact = artifact;
    }

    @Override
    public boolean storedInGroupDirectory() {

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 */
@Deprecated
public class ModelValidationResult {

    /** */
    private static final String LS = System.lineSeparator();

    /** */
    private List<String> messages;

    public ModelValidationResult() {
        messages = new ArrayList<>();
    }

    public int getMessageCount() {
        return messages.size();