Removes one newline from end of a String if it's there, otherwise leave it alone. : String Format « Data Type « Java Tutorial

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import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;

/* 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *
 */
public class Main {
  /**
   * <code>\u000a</code> linefeed LF ('\n').
   * 
   * @see <a href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#101089">JLF: Escape Sequences
   *      for Character and String Literals</a>
   * @since 2.2
   */
  public static final char LF = '\n';

  /**
   * <code>\u000d</code> carriage return CR ('\r').
   * 
   * @see <a href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#101089">JLF: Escape Sequences
   *      for Character and String Literals</a>
   * @since 2.2
   */
  public static final char CR = '\r';
  /**
   * Removes one newline from end of a String if it's there,
   * otherwise leave it alone.  A newline is &quot;<code>\n</code>&quot;,
   * &quot;<code>\r</code>&quot;, or &quot;<code>\r\n</code>&quot;.
   *
   * NOTE: This method changed in 2.0.
   * It now more closely matches Perl chomp.
   *
   * <pre>
   * StringUtils.chomp(null)          = null
   * StringUtils.chomp("")            = ""
   * StringUtils.chomp("abc \r")      = "abc "
   * StringUtils.chomp("abc\n")       = "abc"
   * StringUtils.chomp("abc\r\n")     = "abc"
   * StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
   * StringUtils.chomp("abc\n\r")     = "abc\n"
   * StringUtils.chomp("abc\n\rabc")  = "abc\n\rabc"
   * StringUtils.chomp("\r")          = ""
   * StringUtils.chomp("\n")          = ""
   * StringUtils.chomp("\r\n")        = ""
   * </pre>
   *
   * @param str  the String to chomp a newline from, may be null
   * @return String without newline, <code>null</code> if null String input
   */
  public static String chomp(String str) {
      if (isEmpty(str)) {
          return str;
      }

      if (str.length() == 1) {
          char ch = str.charAt(0);
          if (ch == CR || ch == LF) {
              return "";
          }
          return str;
      }

      int lastIdx = str.length() - 1;
      char last = str.charAt(lastIdx);

      if (last == LF) {
          if (str.charAt(lastIdx - 1) == CR) {
              lastIdx--;
          }
      } else if (last != CR) {
          lastIdx++;
      }
      return str.substring(0, lastIdx);
  }
  // Empty checks
  //-----------------------------------------------------------------------
  /**
   * Checks if a String is empty ("") or null.
   *
   * <pre>
   * StringUtils.isEmpty(null)      = true
   * StringUtils.isEmpty("")        = true
   * StringUtils.isEmpty(" ")       = false
   * StringUtils.isEmpty("bob")     = false
   * StringUtils.isEmpty("  bob  ") = false
   * </pre>
   *
   * NOTE: This method changed in Lang version 2.0.
   * It no longer trims the String.
   * That functionality is available in isBlank().
   *
   * @param str  the String to check, may be null
   * @return <code>true</code> if the String is empty or null
   */
  public static boolean isEmpty(String str) {
      return str == null || str.length() == 0;
  }
}