public static boolean isNumeric(String str) { 
    if (str == null) { 
      return false; 
    } 
    int sz = str.length(); 
    for (int i = 0; i < sz; i++) { 
      if (Character.isDigit(str.charAt(i)) == false) { 
        return false; 
      } 
    } 
    return true; 
  } 

package com.sap.cesp.creditinsight.web.app.util; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
 
public class NumberValidationUtils { 
   
  private static boolean isMatch(String regex, String orginal){ 
    if (orginal == null || orginal.trim().equals("")) { 
      return false; 
    } 
    Pattern pattern = Pattern.compile(regex); 
    Matcher isNum = pattern.matcher(orginal); 
    return isNum.matches(); 
  } 
 
  public static boolean isPositiveInteger(String orginal) { 
    return isMatch("^\\+{0,1}[1-9]\\d*", orginal); 
  } 
 
  public static boolean isNegativeInteger(String orginal) { 
    return isMatch("^-[1-9]\\d*", orginal); 
  } 
 
  public static boolean isWholeNumber(String orginal) { 
    return isMatch("[+-]{0,1}0", orginal) || isPositiveInteger(orginal) || isNegativeInteger(orginal); 
  } 
   
  public static boolean isPositiveDecimal(String orginal){ 
    return isMatch("\\+{0,1}[0]\\.[1-9]*|\\+{0,1}[1-9]\\d*\\.\\d*", orginal); 
  } 
   
  public static boolean isNegativeDecimal(String orginal){ 
    return isMatch("^-[0]\\.[1-9]*|^-[1-9]\\d*\\.\\d*", orginal); 
  } 
   
  public static boolean isDecimal(String orginal){ 
    return isMatch("[-+]{0,1}\\d+\\.\\d*|[-+]{0,1}\\d*\\.\\d+", orginal); 
  } 
   
  public static boolean isRealNumber(String orginal){ 
    return isWholeNumber(orginal) || isDecimal(orginal); 
  } 
 
} 

package com.sap.cesp.creditinsight.web.app.util; 
 
import junit.framework.Assert; 
 
import org.junit.Test; 
 
public class NumberValidationUtilsTest { 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isPositiveInteger(java.lang.String)} 
   */ 
  //correct test case: 1, 87653521123567 
  //wrong test case: 0.1, 0, 0123, -1, -0.1, ab 
  @Test 
  public void testIsPositiveInteger() { 
    Assert.assertTrue(NumberValidationUtils.isPositiveInteger("1")); 
    Assert.assertTrue(NumberValidationUtils.isPositiveInteger("+12")); 
    Assert.assertTrue(NumberValidationUtils.isPositiveInteger("87653521123567")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveInteger("0.1")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveInteger("0")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveInteger("0123")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveInteger("-1")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveInteger("-0.1")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveInteger("ab")); 
  } 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isNegativeInteger(java.lang.String)} 
   */ 
  //correct test case: -1, -87653521123567 
  //wrong test case: 0.1, 0, 0123, 1, -0.1, -ab 
  @Test 
  public void testIsNegativeInteger() { 
    Assert.assertTrue(NumberValidationUtils.isNegativeInteger("-1")); 
    Assert.assertTrue(NumberValidationUtils.isNegativeInteger("-87653521123567")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeInteger("0.1")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeInteger("0")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeInteger("0123")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeInteger("1")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeInteger("-0.1")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeInteger("ab")); 
  } 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isWholeNumber(java.lang.String)}. 
   */ 
  //correct test case: -1, 0, 1, 8673434231, -282464334 
  //wrong test case: 0.1, 0123, -0.1, ab 
  @Test 
  public void testIsWholeNumber() { 
    Assert.assertTrue(NumberValidationUtils.isWholeNumber("-1")); 
    Assert.assertTrue(NumberValidationUtils.isWholeNumber("0")); 
    Assert.assertTrue(NumberValidationUtils.isWholeNumber("1")); 
    Assert.assertTrue(NumberValidationUtils.isWholeNumber("+12")); 
    Assert.assertTrue(NumberValidationUtils.isWholeNumber("8673434231")); 
    Assert.assertTrue(NumberValidationUtils.isWholeNumber("-282464334")); 
    Assert.assertFalse(NumberValidationUtils.isWholeNumber("0123")); 
    Assert.assertFalse(NumberValidationUtils.isWholeNumber("0.1")); 
    Assert.assertFalse(NumberValidationUtils.isWholeNumber("-0.1")); 
    Assert.assertFalse(NumberValidationUtils.isWholeNumber("ab")); 
  } 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isPositiveDecimal(java.lang.String)} 
   */ 
  //correct test case: 0.1, 0.132213, 1.0 
  //wrong test case: 1, 0.0, 0123, -1, -0.1 
  @Test 
  public void testIsPositiveDecimal() { 
    Assert.assertTrue(NumberValidationUtils.isPositiveDecimal("0.1")); 
    Assert.assertTrue(NumberValidationUtils.isPositiveDecimal("0.132213")); 
    Assert.assertTrue(NumberValidationUtils.isPositiveDecimal("30.00")); 
    Assert.assertTrue(NumberValidationUtils.isDecimal("0.")); 
    Assert.assertTrue(NumberValidationUtils.isPositiveDecimal("+12.0")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveDecimal("0123")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveDecimal("1")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveDecimal("0.0")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveDecimal("ab")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveDecimal("-1")); 
    Assert.assertFalse(NumberValidationUtils.isPositiveDecimal("-0.1")); 
  } 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isNegativeDecimal(java.lang.String)} 
   */ 
  //correct test case: -0.132213, -1.0 
  //wrong test case: 1, 0, 0123, -1, 0.1 
  @Test 
  public void testIsNegativeDecimal() { 
    Assert.assertTrue(NumberValidationUtils.isNegativeDecimal("-0.132213")); 
    Assert.assertTrue(NumberValidationUtils.isNegativeDecimal("-1.0")); 
    Assert.assertTrue(NumberValidationUtils.isDecimal("-0.")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("1")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("0")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("0123")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("0.0")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("ab")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("-1")); 
    Assert.assertFalse(NumberValidationUtils.isNegativeDecimal("0.1")); 
  } 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isDecimal(java.lang.String)}. 
   */ 
  //correct test case: 0.1, 0.00, -0.132213 
  //wrong test case: 1, 0, 0123, -1, 0., ba 
  @Test 
  public void testIsDecimal() { 
    Assert.assertTrue(NumberValidationUtils.isDecimal("0.1")); 
    Assert.assertTrue(NumberValidationUtils.isDecimal("0.00")); 
    Assert.assertTrue(NumberValidationUtils.isDecimal("+0.0")); 
    Assert.assertTrue(NumberValidationUtils.isDecimal("-0.132213")); 
    Assert.assertTrue(NumberValidationUtils.isDecimal("0.")); 
    Assert.assertFalse(NumberValidationUtils.isDecimal("1")); 
    Assert.assertFalse(NumberValidationUtils.isDecimal("0123")); 
    Assert.assertFalse(NumberValidationUtils.isDecimal("0")); 
    Assert.assertFalse(NumberValidationUtils.isDecimal("ab")); 
    Assert.assertFalse(NumberValidationUtils.isDecimal("-1")); 
     
  } 
 
  /** 
   * Test method for {@link com.sap.cesp.creditinsight.web.app.util.NumberValidationUtils#isRealNumber(java.lang.String)}. 
   */ 
  //correct test case: 0.032213, -0.234, 0.0, 1, -1, 0 
  //wrong test case: 00.13, ab, +0.14 
  @Test 
  public void testIsRealNumber() { 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("0.032213")); 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("-0.234")); 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("0.0")); 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("1")); 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("+0.14")); 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("-1")); 
    Assert.assertTrue(NumberValidationUtils.isRealNumber("0.0")); 
    Assert.assertFalse(NumberValidationUtils.isRealNumber("00.13")); 
    Assert.assertFalse(NumberValidationUtils.isRealNumber("ab")); 
     
  } 
 
}