读取Boolean类型的系统变量，为空时返回null，代表未设置，而不是Boolean.getBoolean()的false.
328557
public static Boolean getBoolean(String name) {
		String stringResult = System.getProperty(name);
		return BooleanUtil.toBooleanObject(stringResult);
	}
374780
public static Boolean toBoolean(Object o) throws PageException {
	if (o instanceof Boolean) return (Boolean) o;
	return toBooleanValue(o) ? Boolean.TRUE : Boolean.FALSE;

    }
402474
public static boolean isBoolean( Class clazz ) {
      return clazz != null
            && (Boolean.TYPE.isAssignableFrom( clazz ) || Boolean.class.isAssignableFrom( clazz ));
   }
363989
public Boolean getValueBoolean(String label) {
        PrimitiveObject o = getPrimitiveObject(VALUE, label, ObjectUtil.BOOLEAN, "Boolean");
        if (o == null) {
            return null;
        }
        return (Boolean) o.getObject();
    }
1320821
public boolean getBoolean(String name) throws JSONException {
		Object object = get(name);
		Boolean result = JSON.toBoolean(object);
		if (result == null) {
			throw JSON.typeMismatch(name, object, "boolean");
		}
		return result;
	}
647482
public boolean getBoolean(int columnIndex) {
		Object fieldValue = data[columnIndex];
		if (fieldValue == null) {
			return Boolean.FALSE;
		}
		if (fieldValue instanceof Boolean) {
			return (Boolean) fieldValue;
		}
		throw new DBFException("Unsupported type for Boolean at column:" + columnIndex + " "
				+ fieldValue.getClass().getCanonicalName());
	}
819921
protected static boolean getBoolean(final Context context, final DataSource source) throws FlowException {

		if (source != null) {

			final Object value = source.get(context);
			if (value instanceof Boolean) {

				return (Boolean)value;
			}

			if (value instanceof String) {

				return Boolean.valueOf((String)value);
			}
		}

		return false;
	}
888761
public static boolean getBoolean(JSONValue value) {
        if (value == null)
            return false;
        if (!(value instanceof JSONBoolean))
            throw new JSONException(NOT_A_BOOLEAN);
        return ((JSONBoolean)value).booleanValue();
    }
1270829
@Override
    public final boolean getBool(final int i) {
        try {
            return this.array.getBoolean(i);
        } catch (JSONException e) {
            throw new ObjectMissingException(this, "[" + i + "]");
        }
    }
1045495
public synchronized boolean getBoolean()
   {
      final byte value = get();
      if(value == CommsConstants.TRUE_BYTE) return true;
      else if(value == CommsConstants.FALSE_BYTE) return false;
      else throw new IllegalStateException("Unexpected byte: " + value);     
   }
444099
public boolean getBoolean(String key, boolean defaultValue) {
    Object value = get(key);
    if (value instanceof Boolean) {
      return (boolean) value;
    } else if (value instanceof String) {
      return Boolean.valueOf((String) value);
    }
    return defaultValue;
  }
583680
public boolean getBoolean(String fieldName) throws DbfException {
        Boolean value = (Boolean) get(fieldName);
        return value != null && value;
    }
96433
public static final Boolean parseBoolean(String value)
   {
      return (value == null || value.charAt(0) != '1' ? Boolean.FALSE : Boolean.TRUE);
   }
963240
function isBoolean(o) {
    return o !== undefined && o !== null &&
          (typeof o === "boolean" || o.constructor === Boolean);
}
674857
public Boolean getAsBoolean() {
		if (value instanceof String) {
			return Boolean.parseBoolean((String)value);
		}
		return (Boolean)value;
	}
251196
protected Boolean checkBoolean(Object val, Boolean def) {
        return (val == null) ? def : (Boolean) val;
    }
1080016
public static boolean parseBoolean(String bool, boolean defaultInt) {
        if (bool == null) {
            return defaultInt;
        } else {
            return Boolean.parseBoolean(bool);
        }
    }